Is it possible to execute two separate classes with one single java command?
I would like to run a few java programs concurrently (it should start at the same time) for my project.
Example: I have two java programs A.java and B.java.
javac A.java B.java
java A B
However this doesn't work. How else can I do this?
No, the java command simply does not work like that.
Instead have a C.java that calls both A & B classes.
Make a class, say Parallel having as command line arguments the other class names.
Then start for each class a new thread and call its main.
Probably can be done neater.
java Parallel A B
public class Parallel {
public static void main(String[] args) {
for (String arg : args) {
try {
Class<?> klazz = Class.forName(arg);
final Method mainMethod = klazz.getDeclaredMethod("main",
String[].class);
if (mainMethod.getReturnType() != void.class) {
throw new NoSuchMethodException("main not returning void");
}
int modifiers = mainMethod.getModifiers();
if (!Modifier.isStatic(modifiers)
|| !Modifier.isPublic(modifiers)) {
throw new NoSuchMethodException("main not public static");
}
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
try {
mainMethod.invoke(null, (Object)new String[0]);
} catch (IllegalAccessException
| IllegalArgumentException
| InvocationTargetException ex) {
Logger.getLogger(Parallel.class.getName())
.log(Level.SEVERE, null, ex);
}
}
});
thread.start();
} catch (ClassNotFoundException
| NoSuchMethodException
| SecurityException ex) {
Logger.getLogger(Parallel.class.getName())
.log(Level.SEVERE, null, ex);
}
}
}
}
No, the CPU will allways start one one command as first, what you can do is to let both threads wait for some notification which signals them to start, but even then i would guess internally one of them will start befor the other.
No matter how hard u try to start them simultaneously, the output will not be consistent. This won't work even if you try to load them through the third class.
What you can do is you need to handle this logic in your code. Possible options are -
