Java Runtime.getRuntime().exec

Question

I am trying to merge 2 simple programs I have made to one .jar. I packed both .jars into a new one and used Runtime.getRuntime().exec method to execute them.

Code:

public class main {
  public static void main(String[] args) {
    try {
      Runtime.getRuntime().exec("cmd /c proj1.jar");
    } catch(Exception exce){ 
      /*handle exception*/
      try {
        Runtime.getRuntime().exec("cmd /c proj2.jar");
      } catch(Exception exc){
        /*handle exception*/

      }
    }
  }
}

The problem is that only proj1.jar is executed and proj2.jar doesn't run. I am new to java and don't know why this happens. How do I fix this? I want both files to be executed.

Are you sure if the first one is not throwing exception? Can you try printing the stack trace! — Vishal Biyani
– Vishal Biyani, Commented Jun 19, 2012 at 17:26

Nathaniel Ford · Accepted Answer · 2012-06-19 17:26:29Z

7

Your problem is that your second file is ONLY executed if the first throws an exeception. You're looking for this:

public class main {
  public static void main(String[] args) {
    try {
      Runtime.getRuntime().exec("cmd /c proj1.jar");
      Runtime.getRuntime().exec("cmd /c proj2.jar");
    } catch(Exception exce){ 
      /*handle exception*/
    }
  }
}

Or, if you absolutely must handle the exceptions separately, this:

public class main {
  public static void main(String[] args) {
    try {
      Runtime.getRuntime().exec("cmd /c proj1.jar");
    } catch(Exception exce){ 
      /*handle exception*/
    }

    try {
      Runtime.getRuntime().exec("cmd /c proj2.jar");
    } catch (Exception e) {
      //handle the exception
    }
  }
}

answered Jun 19, 2012 at 17:26

Nathaniel Ford

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2 Comments

Denys Séguret Over a year ago

+1 Your edit of the original code changes everything ! I didn't even see the imbrication...

Nathaniel Ford Over a year ago

This is why code formatting is actually super important. It establishes clarity! Problems just fall away!

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