When do you use Java s Override annotation and why

Question

What are the best practices for using Java s  Override annotation and why      It seems like it would be overkill to mark every single overridden method with the  Override annotation    Are there certain programming situations that call for using the  Override and others that should never use the  Override

User · Answer

I always use the tag   It is a simple compile-time flag to catch little mistakes that I might make   It will catch things like tostring   instead of toString    The little things help in large projects

User · Answer

Use it every time you override a method for two benefits   Do it so that you can take advantage of the compiler checking to make sure you actually are overriding a method when you think you are   This way  if you make a common mistake of misspelling a method name or not correctly matching the parameters  you will be warned that you method does not actually override as you think it does   Secondly  it makes your code easier to understand because it is more obvious when methods are overwritten   Additionally  in Java 1 6 you can use it to mark when a method implements an interface for the same benefits   I think it would be better to have a separate annotation  like  Implements   but it s better than nothing

User · Answer

Its best to use it for every method intended as an override  and Java 6   every method intended as an implementation of an interface   First  it catches misspellings like  hashcode    instead of  hashCode    at compile-time  It can be baffling to debug why the result of your method doesn t seem to match your code when the real cause is that your code is never invoked   Also  if a superclass changes a method signature  overrides of the older signature can be  orphaned   left behind as confusing dead code  The  Override annotation will help you identify these orphans so that they can be modified to match the new signature

User · Answer

Override on interfaces actually are helpful  because you will get warnings if you change the interface

User · Answer

There are many good answers here  so let me offer another way to look at it     There is no overkill when you are coding   It doesn t cost you anything to type  override  but the savings can be immense if you misspelled a method name or got the signature slightly wrong   Think about it this way  In the time you navigated here and typed this post  you pretty much used more time than you will spend typing  override for the rest of your life  but one error it prevents can save you hours   Java does all it can to make sure you didn t make any mistakes at edit compile time  this is a virtually free way to solve an entire class of mistakes that aren t preventable in any other way outside of comprehensive testing   Could you come up with a better mechanism in Java to ensure that when the user intended to override a method  he actually did   Another neat effect is that if you don t provide the annotation it will warn you at compile time that you accidentally overrode a parent method--something that could be significant if you didn t intend to do it

User · Answer

The annotation  Override is used for helping to check whether the developer what to override the correct method in the parent class or interface  When the name of super s methods changing  the compiler can notify that case  which is only for keep consistency with the super and the subclass    BTW  if we didn t announce the annotation  Override in the subclass  but we do override some methods of the super  then the function can work as that one with the  Override  But this method can not notify the developer when the super s method was changed  Because it did not know the developer s purpose -- override super s method or define a new method    So when we want to override that method to make use of the Polymorphism  we have better to add  Override above the method

User · Answer

It seems that the wisdom here is changing  Today I installed IntelliJ IDEA 9 and noticed that its  missing  Override inspection  now catches not just implemented abstract methods  but implemented interface methods as well  In my employer s code base and in my own projects  I ve long had the habit to only use  Override for the former -- implemented abstract methods  However  rethinking the habit  the merit of using the annotations in both cases becomes clear  Despite being more verbose  it does protect against the fragile base class problem  not as grave as C  -related examples  where the interface method name changes  orphaning the would-be implementing method in a derived class   Of course  this scenario is mostly hyperbole  the derived class would no longer compile  now lacking an implementation of the renamed interface method  and today one would likely use a Rename Method refactoring operation to address the entire code base en masse   Given that IDEA s inspection is not configurable to ignore implemented interface methods  today I ll change both my habit and my team s code review criteria

User · Answer

Annotations do provide meta data about the code  to the Compiler and the annotation  Override is used in case of inheritance when we are overriding any method of base class  It just tells the compiler that you are overriding method  It can avoide some kinds common mistakes we can do like not following the proper signature of the method or mispelling in name of the method etc  So its a good practice to use  Override annotation

User · Answer

For me the  Override ensures me I have the signature of the method correct   If I put in the annotation and the method is not correctly spelled  then the compiler complains letting me know something is wrong

User · Answer

The annotation  Override is used for helping to check whether the developer what to override the correct method in the parent class or interface  When the name of super s methods changing  the compiler can notify that case  which is only for keep consistency with the super and the subclass    BTW  if we didn t announce the annotation  Override in the subclass  but we do override some methods of the super  then the function can work as that one with the  Override  But this method can not notify the developer when the super s method was changed  Because it did not know the developer s purpose -- override super s method or define a new method    So when we want to override that method to make use of the Polymorphism  we have better to add  Override above the method

User · Answer

Use it every time you override a method for two benefits   Do it so that you can take advantage of the compiler checking to make sure you actually are overriding a method when you think you are   This way  if you make a common mistake of misspelling a method name or not correctly matching the parameters  you will be warned that you method does not actually override as you think it does   Secondly  it makes your code easier to understand because it is more obvious when methods are overwritten   Additionally  in Java 1 6 you can use it to mark when a method implements an interface for the same benefits   I think it would be better to have a separate annotation  like  Implements   but it s better than nothing

User · Answer

The best practive is to always use it  or have the IDE fill them for you    Override usefulness is to detect changes in parent classes which has not been reported down the hierarchy  Without it  you can change a method signature and forget to alter its overrides  with  Override  the compiler will catch it for you   That kind of safety net is always good to have

User · Answer

There are many good answers here  so let me offer another way to look at it     There is no overkill when you are coding   It doesn t cost you anything to type  override  but the savings can be immense if you misspelled a method name or got the signature slightly wrong   Think about it this way  In the time you navigated here and typed this post  you pretty much used more time than you will spend typing  override for the rest of your life  but one error it prevents can save you hours   Java does all it can to make sure you didn t make any mistakes at edit compile time  this is a virtually free way to solve an entire class of mistakes that aren t preventable in any other way outside of comprehensive testing   Could you come up with a better mechanism in Java to ensure that when the user intended to override a method  he actually did   Another neat effect is that if you don t provide the annotation it will warn you at compile time that you accidentally overrode a parent method--something that could be significant if you didn t intend to do it

User · Answer

Using the  Override annotation acts as a compile-time safeguard against a common programming mistake  It will throw a compilation error if you have the annotation on a method you re not actually overriding the superclass method   The most common case where this is useful is when you are changing a method in the base class to have a different parameter list  A method in a subclass that used to override the superclass method will no longer do so due the changed method signature  This can sometimes cause strange and unexpected behavior  especially when dealing with complex inheritance structures  The  Override annotation safeguards against this

User · Answer

I think it is most useful as a compile-time reminder that the intention of the method is to override a parent method   As an example   protected boolean displaySensitiveInformation       return false      You will often see something like the above method that overrides a method in the base class   This is an important implementation detail of this class -- we don t want sensitive information to be displayed     Suppose this method is changed in the parent class to   protected boolean displaySensitiveInformation Context context      return true      This change will not cause any compile time errors or warnings - but it completely changes the intended behavior of the subclass   To answer your question   you should use the  Override annotation if the lack of a method with the same signature in a superclass is indicative of a bug

User · Answer

Override annotation is used to take advantage of the compiler  for checking whether you actually are overriding a method from parent class  It is used to notify if you make any mistake like mistake of misspelling a method name  mistake of not correctly matching the parameters

User · Answer

I use it every time  It s more information that I can use to quickly figure out what is going on when I revisit the code in a year and I ve forgotten what I was thinking the first time

User · Answer

It does allow you  well  the compiler  to catch when you ve used the wrong spelling on a method name you are overriding

User · Answer

Another thing it does is it makes it more obvious when reading the code that it is changing the behavior of the parent class  Than can help in debugging   Also  in Joshua Block s book Effective Java  2nd edition   item 36 gives more details on the benefits of the annotation

User · Answer

I use it everywhere  On the topic of the effort for marking methods  I let Eclipse do it for me so  it s no additional effort   I m religious about continuous refactoring     so  I ll use every little thing to make it go more smoothly

User · Answer

To take advantage from compiler checking you should always use Override annotation  But don   t forget that Java Compiler 1 5 will not allow this annotation when overriding interface methods  You just can use it to override class methods  abstract  or not    Some IDEs  as Eclipse  even configured with Java 1 6 runtime or higher  they maintain compliance with Java 1 5 and don   t allow the use  override as described above  To avoid that behaviour you must go to  Project Properties - Java Compiler -  Check    Enable Project Specific Settings    -  Choose    Compiler Compliance Level      6 0  or higher   I like to use this annotation every time I am overriding a method independently  if the base is an interface  or class    This helps you avoiding some typical errors  as when you are thinking that you are overriding an event handler and then you see nothing happening  Imagine you want to add an event listener to some UI component   someUIComponent addMouseListener new MouseAdapter      public void mouseEntered             do something              The above code compiles and run  but if you move the mouse inside someUIComponent the    do something    code will note run  because actually you are not overriding the base method mouseEntered MouseEvent ev   You just create a new parameter-less method mouseEntered    Instead of that code  if you have used the  Override annotation you have seen a compile error and you have not been wasting time thinking why your event handler was not running

User · Answer

Another thing it does is it makes it more obvious when reading the code that it is changing the behavior of the parent class  Than can help in debugging   Also  in Joshua Block s book Effective Java  2nd edition   item 36 gives more details on the benefits of the annotation

User · Answer

I use it everywhere  On the topic of the effort for marking methods  I let Eclipse do it for me so  it s no additional effort   I m religious about continuous refactoring     so  I ll use every little thing to make it go more smoothly

User · Answer

It seems that the wisdom here is changing  Today I installed IntelliJ IDEA 9 and noticed that its  missing  Override inspection  now catches not just implemented abstract methods  but implemented interface methods as well  In my employer s code base and in my own projects  I ve long had the habit to only use  Override for the former -- implemented abstract methods  However  rethinking the habit  the merit of using the annotations in both cases becomes clear  Despite being more verbose  it does protect against the fragile base class problem  not as grave as C  -related examples  where the interface method name changes  orphaning the would-be implementing method in a derived class   Of course  this scenario is mostly hyperbole  the derived class would no longer compile  now lacking an implementation of the renamed interface method  and today one would likely use a Rename Method refactoring operation to address the entire code base en masse   Given that IDEA s inspection is not configurable to ignore implemented interface methods  today I ll change both my habit and my team s code review criteria

User · Answer

It makes absolutely no sense to use  Override when implementing an interface method  There s no advantage to using it in that case--the compiler will already catch your mistake  so it s just unnecessary clutter

User · Answer

I use it everywhere  On the topic of the effort for marking methods  I let Eclipse do it for me so  it s no additional effort   I m religious about continuous refactoring     so  I ll use every little thing to make it go more smoothly

User · Answer

If you find yourself overriding  non-abstract  methods very often  you probably want to take a look at your design  It is very useful when the compiler would not otherwise catch the error  For instance trying to override initValue   in ThreadLocal  which I have done   Using  Override when implementing interface methods  1 6  feature  seems a bit overkill for me  If you have loads of methods some of which override and some don t  that probably bad design again  and your editor will probably show which is which if you don t know

User · Answer

It does allow you  well  the compiler  to catch when you ve used the wrong spelling on a method name you are overriding

User · Answer

Used only on method declarations  Indicates that the annotated method declaration overrides a declaration in supertype    If used consistently  it protects you from a large class of nefarious bugs    Use  Override annotation to avoid these bugs   Spot the bug in the following code    public class Bigram       private final char first      private final char second      public Bigram char first  char second            this first    first          this second   second            public boolean equals Bigram b            return b first    first  amp  amp  b second    second            public int hashCode             return 31   first   second             public static void main String   args            Set lt Bigram gt  s   new HashSet lt Bigram gt             for  int i   0  i  lt  10  i                for  char ch    a   ch  lt    z   ch                    s add new Bigram ch  ch            System out println s size               source  Effective Java

User · Answer

Override on interfaces actually are helpful  because you will get warnings if you change the interface

User · Answer

Simple   when you want to override a method present in your superclass  use  Override annotation to  make a correct override  The compiler will warn you if you don t override it correctly

User · Answer

It does allow you  well  the compiler  to catch when you ve used the wrong spelling on a method name you are overriding

User · Answer

I use it as much as can to identify when a method is being overriden   If you look at the Scala programming language  they also have an override keyword   I find it useful

User · Answer

It makes absolutely no sense to use  Override when implementing an interface method  There s no advantage to using it in that case--the compiler will already catch your mistake  so it s just unnecessary clutter

User · Answer

I always use the tag   It is a simple compile-time flag to catch little mistakes that I might make   It will catch things like tostring   instead of toString    The little things help in large projects

User · Answer

If you find yourself overriding  non-abstract  methods very often  you probably want to take a look at your design  It is very useful when the compiler would not otherwise catch the error  For instance trying to override initValue   in ThreadLocal  which I have done   Using  Override when implementing interface methods  1 6  feature  seems a bit overkill for me  If you have loads of methods some of which override and some don t  that probably bad design again  and your editor will probably show which is which if you don t know

User · Answer

I use it as much as can to identify when a method is being overriden   If you look at the Scala programming language  they also have an override keyword   I find it useful

User · Answer

Whenever a method overrides another method  or a method implements a signature in an interface   The  Override annotation assures you that you did in fact override something  Without the annotation you risk a misspelling or a difference in parameter types and number

User · Answer

Its best to use it for every method intended as an override  and Java 6   every method intended as an implementation of an interface   First  it catches misspellings like  hashcode    instead of  hashCode    at compile-time  It can be baffling to debug why the result of your method doesn t seem to match your code when the real cause is that your code is never invoked   Also  if a superclass changes a method signature  overrides of the older signature can be  orphaned   left behind as confusing dead code  The  Override annotation will help you identify these orphans so that they can be modified to match the new signature

User · Answer

Another thing it does is it makes it more obvious when reading the code that it is changing the behavior of the parent class  Than can help in debugging   Also  in Joshua Block s book Effective Java  2nd edition   item 36 gives more details on the benefits of the annotation

User · Answer

Using the  Override annotation acts as a compile-time safeguard against a common programming mistake  It will throw a compilation error if you have the annotation on a method you re not actually overriding the superclass method   The most common case where this is useful is when you are changing a method in the base class to have a different parameter list  A method in a subclass that used to override the superclass method will no longer do so due the changed method signature  This can sometimes cause strange and unexpected behavior  especially when dealing with complex inheritance structures  The  Override annotation safeguards against this

User · Answer

Whenever a method overrides another method  or a method implements a signature in an interface   The  Override annotation assures you that you did in fact override something  Without the annotation you risk a misspelling or a difference in parameter types and number

User · Answer

To take advantage from compiler checking you should always use Override annotation  But don   t forget that Java Compiler 1 5 will not allow this annotation when overriding interface methods  You just can use it to override class methods  abstract  or not    Some IDEs  as Eclipse  even configured with Java 1 6 runtime or higher  they maintain compliance with Java 1 5 and don   t allow the use  override as described above  To avoid that behaviour you must go to  Project Properties - Java Compiler -  Check    Enable Project Specific Settings    -  Choose    Compiler Compliance Level      6 0  or higher   I like to use this annotation every time I am overriding a method independently  if the base is an interface  or class    This helps you avoiding some typical errors  as when you are thinking that you are overriding an event handler and then you see nothing happening  Imagine you want to add an event listener to some UI component   someUIComponent addMouseListener new MouseAdapter      public void mouseEntered             do something              The above code compiles and run  but if you move the mouse inside someUIComponent the    do something    code will note run  because actually you are not overriding the base method mouseEntered MouseEvent ev   You just create a new parameter-less method mouseEntered    Instead of that code  if you have used the  Override annotation you have seen a compile error and you have not been wasting time thinking why your event handler was not running

User · Answer

Override on interface implementation is inconsistent since there is no such thing as  overriding an interface  in java     Override on interface implementation is useless since in practise it catches no bugs that the compilation wouldn t catch anyway   There is only one  far fetched scenario where override on implementers actually does something  If you implement an interface  and the interface REMOVES methods  you will be notified on compile time that you should remove the unused implementations  Notice that if the new version of the interface has NEW or CHANGED methods you ll obviously get a compile error anyways as you re not implementing the new stuff    Override on interface implementers should never have been permitted in 1 6  and with eclipse sadly choosing to auto-insert the annotations as default behavior  we get a lot of cluttered source files  When reading 1 6 code  you cannot see from the  Override annotation if a method actually overrides a method in the superclass or just implements an interface   Using  Override when actually overriding a method in a superclass is fine

User · Answer

I use it every time  It s more information that I can use to quickly figure out what is going on when I revisit the code in a year and I ve forgotten what I was thinking the first time

User · Answer

Override on interfaces actually are helpful  because you will get warnings if you change the interface

User · Answer

There are many good answers here  so let me offer another way to look at it     There is no overkill when you are coding   It doesn t cost you anything to type  override  but the savings can be immense if you misspelled a method name or got the signature slightly wrong   Think about it this way  In the time you navigated here and typed this post  you pretty much used more time than you will spend typing  override for the rest of your life  but one error it prevents can save you hours   Java does all it can to make sure you didn t make any mistakes at edit compile time  this is a virtually free way to solve an entire class of mistakes that aren t preventable in any other way outside of comprehensive testing   Could you come up with a better mechanism in Java to ensure that when the user intended to override a method  he actually did   Another neat effect is that if you don t provide the annotation it will warn you at compile time that you accidentally overrode a parent method--something that could be significant if you didn t intend to do it

User · Answer

Simple   when you want to override a method present in your superclass  use  Override annotation to  make a correct override  The compiler will warn you if you don t override it correctly

User · Answer

Using the  Override annotation acts as a compile-time safeguard against a common programming mistake  It will throw a compilation error if you have the annotation on a method you re not actually overriding the superclass method   The most common case where this is useful is when you are changing a method in the base class to have a different parameter list  A method in a subclass that used to override the superclass method will no longer do so due the changed method signature  This can sometimes cause strange and unexpected behavior  especially when dealing with complex inheritance structures  The  Override annotation safeguards against this

User · Answer

Use it every time you override a method for two benefits   Do it so that you can take advantage of the compiler checking to make sure you actually are overriding a method when you think you are   This way  if you make a common mistake of misspelling a method name or not correctly matching the parameters  you will be warned that you method does not actually override as you think it does   Secondly  it makes your code easier to understand because it is more obvious when methods are overwritten   Additionally  in Java 1 6 you can use it to mark when a method implements an interface for the same benefits   I think it would be better to have a separate annotation  like  Implements   but it s better than nothing

User · Answer

Be careful when you use Override  because you can t do reverse engineer in starUML afterwards  make the uml first

User · Answer

I always use the tag   It is a simple compile-time flag to catch little mistakes that I might make   It will catch things like tostring   instead of toString    The little things help in large projects

User · Answer

If you find yourself overriding  non-abstract  methods very often  you probably want to take a look at your design  It is very useful when the compiler would not otherwise catch the error  For instance trying to override initValue   in ThreadLocal  which I have done   Using  Override when implementing interface methods  1 6  feature  seems a bit overkill for me  If you have loads of methods some of which override and some don t  that probably bad design again  and your editor will probably show which is which if you don t know

User · Answer

I always use the tag   It is a simple compile-time flag to catch little mistakes that I might make   It will catch things like tostring   instead of toString    The little things help in large projects

User · Answer

Whenever a method overrides another method  or a method implements a signature in an interface   The  Override annotation assures you that you did in fact override something  Without the annotation you risk a misspelling or a difference in parameter types and number

User · Answer

Whenever a method overrides another method  or a method implements a signature in an interface   The  Override annotation assures you that you did in fact override something  Without the annotation you risk a misspelling or a difference in parameter types and number

User · Answer

There are many good answers here  so let me offer another way to look at it     There is no overkill when you are coding   It doesn t cost you anything to type  override  but the savings can be immense if you misspelled a method name or got the signature slightly wrong   Think about it this way  In the time you navigated here and typed this post  you pretty much used more time than you will spend typing  override for the rest of your life  but one error it prevents can save you hours   Java does all it can to make sure you didn t make any mistakes at edit compile time  this is a virtually free way to solve an entire class of mistakes that aren t preventable in any other way outside of comprehensive testing   Could you come up with a better mechanism in Java to ensure that when the user intended to override a method  he actually did   Another neat effect is that if you don t provide the annotation it will warn you at compile time that you accidentally overrode a parent method--something that could be significant if you didn t intend to do it

User · Answer

It does allow you  well  the compiler  to catch when you ve used the wrong spelling on a method name you are overriding

User · Answer

The best practive is to always use it  or have the IDE fill them for you    Override usefulness is to detect changes in parent classes which has not been reported down the hierarchy  Without it  you can change a method signature and forget to alter its overrides  with  Override  the compiler will catch it for you   That kind of safety net is always good to have

User · Answer

For me the  Override ensures me I have the signature of the method correct   If I put in the annotation and the method is not correctly spelled  then the compiler complains letting me know something is wrong

User · Answer

Be careful when you use Override  because you can t do reverse engineer in starUML afterwards  make the uml first

User · Answer

I use it everywhere  On the topic of the effort for marking methods  I let Eclipse do it for me so  it s no additional effort   I m religious about continuous refactoring     so  I ll use every little thing to make it go more smoothly

User · Answer

i think it s best to code the  override whenever allowed  it helps for coding  however  to be noted  for ecipse Helios  either sdk 5 or 6  the  override annotation for implemented interface methods is allowed  as for Galileo  either 5 or 6   override annotation is not allowed

User · Answer

Override on interface implementation is inconsistent since there is no such thing as  overriding an interface  in java     Override on interface implementation is useless since in practise it catches no bugs that the compilation wouldn t catch anyway   There is only one  far fetched scenario where override on implementers actually does something  If you implement an interface  and the interface REMOVES methods  you will be notified on compile time that you should remove the unused implementations  Notice that if the new version of the interface has NEW or CHANGED methods you ll obviously get a compile error anyways as you re not implementing the new stuff    Override on interface implementers should never have been permitted in 1 6  and with eclipse sadly choosing to auto-insert the annotations as default behavior  we get a lot of cluttered source files  When reading 1 6 code  you cannot see from the  Override annotation if a method actually overrides a method in the superclass or just implements an interface   Using  Override when actually overriding a method in a superclass is fine

User · Answer

The best practive is to always use it  or have the IDE fill them for you    Override usefulness is to detect changes in parent classes which has not been reported down the hierarchy  Without it  you can change a method signature and forget to alter its overrides  with  Override  the compiler will catch it for you   That kind of safety net is always good to have

User · Answer

I use it every time  It s more information that I can use to quickly figure out what is going on when I revisit the code in a year and I ve forgotten what I was thinking the first time

User · Answer

I think it is most useful as a compile-time reminder that the intention of the method is to override a parent method   As an example   protected boolean displaySensitiveInformation       return false      You will often see something like the above method that overrides a method in the base class   This is an important implementation detail of this class -- we don t want sensitive information to be displayed     Suppose this method is changed in the parent class to   protected boolean displaySensitiveInformation Context context      return true      This change will not cause any compile time errors or warnings - but it completely changes the intended behavior of the subclass   To answer your question   you should use the  Override annotation if the lack of a method with the same signature in a superclass is indicative of a bug

User · Answer

If you find yourself overriding  non-abstract  methods very often  you probably want to take a look at your design  It is very useful when the compiler would not otherwise catch the error  For instance trying to override initValue   in ThreadLocal  which I have done   Using  Override when implementing interface methods  1 6  feature  seems a bit overkill for me  If you have loads of methods some of which override and some don t  that probably bad design again  and your editor will probably show which is which if you don t know

User · Answer

The best practive is to always use it  or have the IDE fill them for you    Override usefulness is to detect changes in parent classes which has not been reported down the hierarchy  Without it  you can change a method signature and forget to alter its overrides  with  Override  the compiler will catch it for you   That kind of safety net is always good to have

User · Answer

Annotations do provide meta data about the code  to the Compiler and the annotation  Override is used in case of inheritance when we are overriding any method of base class  It just tells the compiler that you are overriding method  It can avoide some kinds common mistakes we can do like not following the proper signature of the method or mispelling in name of the method etc  So its a good practice to use  Override annotation

User · Answer

I think it is most useful as a compile-time reminder that the intention of the method is to override a parent method   As an example   protected boolean displaySensitiveInformation       return false      You will often see something like the above method that overrides a method in the base class   This is an important implementation detail of this class -- we don t want sensitive information to be displayed     Suppose this method is changed in the parent class to   protected boolean displaySensitiveInformation Context context      return true      This change will not cause any compile time errors or warnings - but it completely changes the intended behavior of the subclass   To answer your question   you should use the  Override annotation if the lack of a method with the same signature in a superclass is indicative of a bug

User · Answer

Using the  Override annotation acts as a compile-time safeguard against a common programming mistake  It will throw a compilation error if you have the annotation on a method you re not actually overriding the superclass method   The most common case where this is useful is when you are changing a method in the base class to have a different parameter list  A method in a subclass that used to override the superclass method will no longer do so due the changed method signature  This can sometimes cause strange and unexpected behavior  especially when dealing with complex inheritance structures  The  Override annotation safeguards against this

User · Answer

I use it every time  It s more information that I can use to quickly figure out what is going on when I revisit the code in a year and I ve forgotten what I was thinking the first time

User · Answer

I think it is most useful as a compile-time reminder that the intention of the method is to override a parent method   As an example   protected boolean displaySensitiveInformation       return false      You will often see something like the above method that overrides a method in the base class   This is an important implementation detail of this class -- we don t want sensitive information to be displayed     Suppose this method is changed in the parent class to   protected boolean displaySensitiveInformation Context context      return true      This change will not cause any compile time errors or warnings - but it completely changes the intended behavior of the subclass   To answer your question   you should use the  Override annotation if the lack of a method with the same signature in a superclass is indicative of a bug

User · Answer

Override annotation is used to take advantage of the compiler  for checking whether you actually are overriding a method from parent class  It is used to notify if you make any mistake like mistake of misspelling a method name  mistake of not correctly matching the parameters

User · Answer

Use it every time you override a method for two benefits   Do it so that you can take advantage of the compiler checking to make sure you actually are overriding a method when you think you are   This way  if you make a common mistake of misspelling a method name or not correctly matching the parameters  you will be warned that you method does not actually override as you think it does   Secondly  it makes your code easier to understand because it is more obvious when methods are overwritten   Additionally  in Java 1 6 you can use it to mark when a method implements an interface for the same benefits   I think it would be better to have a separate annotation  like  Implements   but it s better than nothing

User · Answer

Its best to use it for every method intended as an override  and Java 6   every method intended as an implementation of an interface   First  it catches misspellings like  hashcode    instead of  hashCode    at compile-time  It can be baffling to debug why the result of your method doesn t seem to match your code when the real cause is that your code is never invoked   Also  if a superclass changes a method signature  overrides of the older signature can be  orphaned   left behind as confusing dead code  The  Override annotation will help you identify these orphans so that they can be modified to match the new signature

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Used only on method declarations  Indicates that the annotated method declaration overrides a declaration in supertype    If used consistently  it protects you from a large class of nefarious bugs    Use  Override annotation to avoid these bugs   Spot the bug in the following code    public class Bigram       private final char first      private final char second      public Bigram char first  char second            this first    first          this second   second            public boolean equals Bigram b            return b first    first  amp  amp  b second    second            public int hashCode             return 31   first   second             public static void main String   args            Set lt Bigram gt  s   new HashSet lt Bigram gt             for  int i   0  i  lt  10  i                for  char ch    a   ch  lt    z   ch                    s add new Bigram ch  ch            System out println s size               source  Effective Java

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i think it s best to code the  override whenever allowed  it helps for coding  however  to be noted  for ecipse Helios  either sdk 5 or 6  the  override annotation for implemented interface methods is allowed  as for Galileo  either 5 or 6   override annotation is not allowed

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Its best to use it for every method intended as an override  and Java 6   every method intended as an implementation of an interface   First  it catches misspellings like  hashcode    instead of  hashCode    at compile-time  It can be baffling to debug why the result of your method doesn t seem to match your code when the real cause is that your code is never invoked   Also  if a superclass changes a method signature  overrides of the older signature can be  orphaned   left behind as confusing dead code  The  Override annotation will help you identify these orphans so that they can be modified to match the new signature

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Another thing it does is it makes it more obvious when reading the code that it is changing the behavior of the parent class  Than can help in debugging   Also  in Joshua Block s book Effective Java  2nd edition   item 36 gives more details on the benefits of the annotation

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Override on interfaces actually are helpful  because you will get warnings if you change the interface

[java] When do you use Java's @Override annotation and why?

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