如何在没有JVM退出的情况下多次运行Java程序？

Question

Suppose I have a Java program Test.class , if I used the below script

for i in 1..10
do
    java Test
done

the JVM would exit each time java Test is invoked.

What I want is running java Test multiple times without exiting the JVM, so that, the optimized methods in prior runs can be used by later runs, and possibly be further optimized.

Answer 1

为什么不编写一个重复调用要运行的程序入口点的Java程序？

Answer 2

Run this once

java Run

The main Program calling your Test class mulitple times.

class Run {

    public static void main(String[] args) {
        for(int i=0; i<10; i++){
            Test.main(args);
        }
    }
}

Answer 3

public class RunTest
 {
    public static void main(String[] args)
      {
          for(int i=1; i<=10; i++)
              Test.main(args); 
      }
 }

This should do it. You can call the Test class' main function with the same arguments you pass to your main function. This is the "wrapper" that another poster referred to.

Answer 4

Use code like this:

public static void main2(String args[]){ // change main to main2
  for(int i=0;i<10;i++)main(args);
}
public static void main(String args[]){ // REAL main
   //...
}

Answer 5

Perhas a ProcessBuilder would be suitable? Eg, something like

String[] cmd = {"path/to/java", "test"};
ProcessBuilder proc = new ProcessBuilder(cmd);
Process process = proc.start();

Answer 6

What you want to do is put the loop inside the Test class or pass the number of times you want to loop as an argument to the main() inside Test .

NOTE:

If you are looking at JIT optimizations it will take more than 10 iterations to kick in.

Answer 7

Same as previous examples but using command line args

public class Test {

    public static void main(String[] args) {
        if ( args.length > 0) {
            final Integer n = Integer.valueOf(args[0]);
            System.out.println("Running test " + n);
            if ( n > 1 ) {
                main(new String[] { Integer.toString(n-1) });
            }
        }
    }
}

use the args to indicate the number of runs

$ java Test 10