java execute jar file code example

Example 1: run jar file command line

java -jar <jar-file-name>.jar

Example 2: java execute jar from main

java -cp MyJar.jar com.packagename.MainClass [somearg1] [somearg2] [etc]

Example 3: java load jar at runtime

URLClassLoader child = new URLClassLoader(
        new URL[] {myJar.toURI().toURL()},
        this.getClass().getClassLoader()
);
Class classToLoad = Class.forName("com.MyClass", true, child);
Method method = classToLoad.getDeclaredMethod("myMethod");
Object instance = classToLoad.newInstance();
Object result = method.invoke(instance);

Example 4: run jar file with different jre

First, go to the location of the java installation file. By default, this is:
C:\Program Files\Java\...
Open the folder of the java version you want and go to the bin folder.
Copy the directory your at then go to your command line. 
Syntax: (%PATH% is path you copied):
"%PATH%/java.exe" [javaArgs] [filePath] [yourCodeArgs]