How to get the main class name in java

Question

How to get the main class name in any point of my java execution. all that i wanted is i need to get the class name from where my execution has started. Example,

package mypackage;
class A
{
public static sayName()
{
 System.out.println("Here i have to print the class name B");
}
}


package test;
import mypackage.A;

class B
{
public static void main()
{
A.sayName();
}
}

Thanks in advance

I don't think you can. It may not even be on the stacktrace, if you are running on another thread now. — Thilo, Dec 26 '12 at 04:39
Maybe print the stack ? http://stackoverflow.com/questions/1069066/get-current-stack-trace-in-java — S.D., Dec 26 '12 at 04:40
Use a consistent and logical indent for code blocks. The indentation of the code is intended to help people understand the program flow. — Andrew Thompson, Dec 26 '12 at 04:51

score 3 · Answer 1 · answered Dec 26 '12 at 04:45

3

See if this works.

StackTraceElement[] stack = Thread.currentThread ().getStackTrace ();
StackTraceElement main = stack[stack.length - 1];
String mainClass = main.getClassName ();

But I am not sure if it will work if execution of this code has another thread of control other than main thread.

answered Dec 26 '12 at 04:45

Vallabh Patade

4,960
6
31
40

2

This can again be usefull. Try using Thread.getAllStackTraces(). It returns a Map of the stack traces from all running threads, not just the current one. – Vallabh Patade Dec 26 '12 at 04:46
4

What if Thread which started main() finished? – tcb Dec 26 '12 at 05:39

score 0 · Answer 2 · answered Dec 26 '12 at 04:49

0

Try this

public static String getMainClassName()
{
  for(final Map.Entry<String, String> entry : System.getenv().entrySet())
  {
    if(entry.getKey().startsWith("JAVA_MAIN_CLASS"))
      return entry.getValue();
  }
  throw new IllegalStateException("Cannot determine main class.")
}

This might work but it's not portable between JVMs.

answered Dec 26 '12 at 04:49

harikrishnan.n0077

1,927
4
21
27

No it doesn't worked for me, Anyway thanks. But the above trick worked. – Karthikeyan Dec 26 '12 at 05:02

score 0 · Answer 3 · answered Dec 26 '12 at 05:36

0

I'll create additional holder class which will hold main class name. Something like that:

public class MainClassHolder{
    private static String className = null;

    public static void setClassName(String name) {
         className = name;
    }
    public static String getClassName() {
         return className;
    }
}

Then in main methot you'll set up className into holder

package mypackage;
class A
{
public static sayName()
{
 System.out.println(MainClassHolder.getClassName());
}
}


package test;
import mypackage.A;

class B
{
public static void main()
{
    MainClassHolder.setClassName(B.class.getName());
    A.sayName();
}
}

answered Dec 26 '12 at 05:36

Timofei

420
1
5
14

Yeah., Nice idea. But when we are working in a project that more conscious about memory, this idea won't be a nice solution. Anyway, thanks for the effort.If i get any issue in getting stack trace., let me use this solution. Thanks for the effort. – Karthikeyan Dec 26 '12 at 05:46
@Karthikeyan,I'll not worry about memory. There is just one class with one static field. But if even this is critical for you - that's not very nice solution. – Timofei Dec 26 '12 at 05:55
You were right, i have got stuck with above solution when i ran the script via testing framework, In which, some class have been called before the main class, so stack[0] does not return my main class. you were awesome. Thanks for the solution. – Karthikeyan Mar 03 '13 at 10:05

How to get the main class name in java

3 Answers3