How to call a method in another class of the same package

Question

How to call a method  which is in another class of same package in Java  What I know is  using an object we can call a method from a different class  Is there any other way to call a method of different class

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By calling method   public class a        void sum int i int k                System out println  THe sum of the number    i k            class b       public static void main String   args                a vc new a            vc sum 10   20

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You can either create a static method or use the other class as a member of your class calling the function in the constructor       public class aClass         private SomeOtherClass oc        public class aClass  SomeOtherClass otherClass             oc   otherClass                 public callOtherClassMethod              oc otherClassMethod

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If you define the method as static you can use it without instantiating the class first  but then you also dont have the object variables available for use   public class Foo      public static String Bar           return  bla            In that case you could call it with Foo Bar

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From the Notes of Fred Swartz  fredosaurus      There are two types of methods    Instance methods are associated with an object and use the instance variables of that object  This is the default  Static methods use no instance variables of any object of the class they are defined in  If you define a method to be static  you will be given a rude message by the compiler if you try to access any instance variables  You can access static variables  but except for constants  this is unusual  Static methods typically take all they data from parameters and compute something from those parameters  with no reference to variables  This is typical of methods which do some kind of generic calculation  A good example of this are the many utility methods in the predefined Math class    Qualifying a static call  From outside the defining class  an instance method is called by prefixing it with an object  which is then passed as an implicit parameter to the instance method  eg  inputTF setText       A static method is called by prefixing it with a class name  eg  Math max i j    Curiously  it can also be qualified with an object  which will be ignored  but the class of the object will be used    Example  Here is a typical static method   class MyUtils                                                                     mean     public static double mean int   p            int sum   0      sum of all the elements         for  int i 0  i lt p length  i                  sum    p i                     return   double sum    p length         endmethod mean               The only data this method uses or changes is from parameters  or local variables of course    Why declare a method static  The above mean   method would work just as well if it wasn t declared static  as long as it was called from within the same class  If called from outside the class and it wasn t declared static  it would have to be qualified  uselessly  with an object  Even when used within the class  there are good reasons to define a method as static when it could be     Documentation  Anyone seeing that a method is static will know how to call it  see below   Similarly  any programmer looking at the code will know that a static method can t interact with instance variables  which makes reading and debugging easier   Efficiency  A compiler will usually produce slightly more efficient code because no implicit object parameter has to be passed to the method     Calling static methods  There are two cases   Called from within the same class  Just write the static method name  Eg      Called from inside the MyUtils class double avgAtt   mean attendance     Called from outside the class  If a method  static or instance  is called from another class  something must be given before the method name to specify the class where the method is defined  For instance methods  this is the object that the method will access  For static methods  the class name should be specified  Eg      Called from outside the MyUtils class  double avgAtt   MyUtils mean attendance      If an object is specified before it  the object value will be ignored and the the class of the object will be used    Accessing static variables  Altho a static method can t access instance variables  it can access static variables  A common use of static variables is to define  constants   Examples from the Java library are Math PI or Color RED  They are qualified with the class name  so you know they are static  Any method  static or not  can access static variables  Instance variables can be accessed only by instance methods    Alternate Call  What s a little peculiar  and not recommended  is that an object of a class may be used instead of the class name to access static methods  This is bad because it creates the impression that some instance variables in the object are used  but this isn t the case

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If it s a static method  you can call it by using the class name in place of an object

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Create an instance of Class B   B b new B    b method      or define an static method in Class B   class B    static void staticMethod        and call it like this   B staticMethod

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Methods are object methods or class methods   Object methods  it applies over an object  You have to use an instance   instance method args        Class methods  it applies over a class  It doesn t have an implicit instance  You have to use the class itself  It s more like procedural programming   ClassWithStaticMethod method args        Reflection  With reflection you have an API to programmatically access methods  be they object or class methods   Instance methods  methodRef invoke instance  args      Class methods  methodRef invoke null  args

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Do it in this format   classmehodisin methodname     For example   MyClass1 clearscreen     I hope this helped   Note The method must be static

[java] How to call a method in another class of the same package?

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