What's the difference between program arguments and VM arguments?

Question

I found only when I put -Dcontext=web into VM arguments, the value can be read by System.getproperty method. I am wondering what\'s the difference betw

Answer 1

Program Argument: Program arguments are arguments that are passed to your application, which are accessible via the "args" String array parameter of your main method.

VM Argument: VM arguments are environment or system argument that needed by JVM to execute the program. VM arguments are read from system property as below java instruction.

System.getProperty(sysProp1)

Code Snippet:

public static void main(String[] args) {
    String sysProp1 = "sysProp1";
    System.out.println("\t System Propery Name:" + sysProp1 + ", Value:" + System.getProperty(sysProp1));
    System.out.println("\t Program Variable Test Propery Name:" + args[0]);
}

There are Two way to pass these two params values.

From Eclipse:

As shown in the figure above

Command Line Argument:

 java -cp -DsysProp1=testing123456 projectJar-2.0-SNAPSHOT-jar-with-dependencies.jar 123

For a better presentation, in multiple lines

 java -cp 
      -DsysProp1=testing123456 
      projectJar-2.0-SNAPSHOT-jar-with-dependencies.jar 
      123