Executing jar file from another jar

Question

I am executing a jar file from another jar file. While accessing resources file from child jar it is giving exception : java.io.FileNotFoundException: File 'file:PATH_TO_CHILD_JAR/example-1.0.0-0-SNAPSHOT-jar-with-dependencies.jar!resource_file_path/abs.sql.tpl' does not exist.

I am not able to figure why it is taking "!" mark while searching for resource files.

Answer 1

you can execute the jar file with in java program.

make sure that you have added Manifest file in the jar which has Main-Class attribute.

My steps and output:

Created manifest file with the following line: Main-Class: com.demo.TestJar

Created Test Java program:

package com.demo;
  public class TestJar extends Object {
  public static void main(String args[]) {
    System.out.println("TestJar");
  }
}

Package the jar : jar cvfm /home/user/TestJarOne.jar manifest.txt

Write test program:

import java.io.BufferedInputStream;
import java.io.IOException;

public class TestJSS extends Object {

static int i = 0;

public static void main(String args[]) throws IOException, InterruptedException {
    System.out.println("Calling jar");
    Process p = Runtime.getRuntime().exec("java -jar /home/user/TestJarOne.jar arg1 arg2");
    BufferedInputStream bis = new BufferedInputStream(p.getInputStream());
    synchronized (p) {
        p.waitFor();
    }
    System.out.println(p.exitValue());
    int b=0;
    while((b=bis.read()) >0){

        System.out.print((char)b);    
    }        
    System.out.println("");
    System.out.println("Called jar");
  }

}

Answer 2

Try this

 // Run a java app in a separate system process
 Process proc = Runtime.getRuntime().exec("java -jar A.jar");
 // Then retreive the process output
 InputStream in = proc.getInputStream();
 InputStream err = proc.getErrorStream();