What is the use of printStackTrace method in Java

Question

I am going through a socket program  In it  printStackTrace is called on the IOException object in the catch block  What does printStackTrace   actually do   catch IOException ioe        ioe printStackTrace        I am unaware of its purpose  What is it used for

User · Accepted Answer

It s a method on Exception instances that prints the stack trace of the instance to System err   It s a very simple  but very useful tool for diagnosing an exceptions  It tells you what happened and where in the code this happened   Here s an example of how it might be used in practice   try                catch  SomeException e         e printStackTrace

User · Answer

What is the use of e printStackTrace   method in Java   Well  the purpose of using this method e printStackTrace    is to see what exactly wrong is    For example  we want to handle an exception  Let s have a look at the following Example   public class Main     public static void main String   args         int a   12      int b   2       try          int result   a    b - 2          System out println result              catch  Exception e               System out println  Error      e getMessage            e printStackTrace                  I ve used method e printStackTrace    in order to show exactly what is wrong    In the output  we can see the following result    Error    by zero  java lang ArithmeticException    by zero    at Main main Main java 10    at sun reflect NativeMethodAccessorImpl invoke0 Native Method    at sun reflect NativeMethodAccessorImpl invoke NativeMethodAccessorImpl java 62    at sun reflect DelegatingMethodAccessorImpl invoke DelegatingMethodAccessorImpl java 43    at java lang reflect Method invoke Method java 498    at com intellij rt execution application AppMain main AppMain java 147

User · Answer

printStackTrace   helps the programmer to understand where the actual problem occurred  printStacktrace   is a method of the class Throwable of java lang package  It prints several lines in the output console   The first line consists of several strings  It contains the name of the Throwable sub-class  amp  the package information   From second line onwards  it describes the error position line number beginning with at    The last line always describes the destination affected by the error exception  The second last line informs us about the next line in the stack where the control goes after getting transfer from the line number described in the last line  The errors exceptions represents the output in the form a stack  which were fed into the stack by fillInStackTrace   method of Throwable class  which itself fills in the program control transfer details into the execution stack  The lines starting with at  are nothing but the values of the execution stack   In this way the programmer can understand where in code the actual problem is   Along with the printStackTrace   method  it s a good idea to use e getmessage

User · Answer

printStackTrace   helps the programmer to understand where the actual problem occurred  It helps to trace the exception  it is printStackTrace   method of Throwable class inherited by every exception class  This method prints the same message of e object and also the line number where the exception occurred   The following is an another example of print stack of the Exception in Java   public class Demo      public static void main String   args          try            ExceptionFunc            catch Throwable e             e printStackTrace                    public static void ExceptionFunc   throws Throwable         Throwable t   new Throwable  This is new Exception in Java              StackTraceElement   trace   new StackTraceElement              new StackTraceElement  ClassName   methodName   fileName  5                 t setStackTrace trace         throw t           java lang Throwable  This is new Exception in Java        at ClassName methodName fileName 5

User · Answer

printStackTrace is a method of the Throwable class  This method displays error message in the console  where we are getting the exception in the source code  These methods can be used with catch block and they describe    Name of the exception  Description of the exception  Location of the exception in the source code    The three methods which describe the exception on the console  in which printStackTrace is one of them  are    printStackTrace   toString   getMessage     Example   public class BabluGope       public static void main String   args            try               System out println 10 0              catch  ArithmeticException e                 e printStackTrace                       System err println e toString                    System err println e getMessage

User · Answer

printStackTrace   tells at what line you are getting error any why are you getting error   Example    java lang ArithmeticException    by zero     at MinNumber main MinNumber java 8

User · Answer

I was kind of curious about this too  so I just put together a little sample code where you can see what it is doing   try       throw new NullPointerException      catch  NullPointerException e        System out println e      try       throw new IOException      catch  IOException e        e printStackTrace      System exit 0     Calling println e       java lang NullPointerException   Calling e printStackTrace      java io IOException       at package Test main Test java 74

User · Answer

printStackTrace   prints the locations where the exception occurred in the source code  thus allowing the author who wrote the program to see what went wrong  But since it shows problems in the source code  the user s  who may or may not have any coding experience may not be able to understand what went wrong  so if the program allows the user to send error messages to the authors  the users may not be able to give good data on what went wrong   You should consider the Logger getLogger   method  it offers a better exception handling  logging  facility  and besides printStackTrace   without arguments is considered to be obsolete and should ONLY be used for debugging purposes  not for user display

User · Answer

The printStackTrace   helps the programmer understand where the actual problem occurred   The printStackTrace   method is a member of the class Throwable in the java lang package

User · Answer

It helps to trace the exception  For example you are writing some methods in your program and one of your methods causes bug  Then printstack will help you to identify which method causes the bug  Stack will help like this   First your main method will be called and inserted to stack  then the second method will be called and inserted to the stack in LIFO order and if any error occurs somewhere inside any method then this stack will help to identify that method

[java] What is the use of printStackTrace() method in Java?

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