i'll try to answer because i can't understand what you mean absolutely.
before i answer, i ask to you , what kind of java  editor you use ?
if you use notepad, it's impossible to do that.
but if you use java editor like JCreator, while we compile the program,
if there any mistake, jcreator will display  error message. if we still
force to execute the program, may be we will see the message  box about the
program's error.
that's all from me. may ny one else can explain about this ???

This is not abt the error message  . I ll explain my doubt  clearly .

While we r executing  a java  program ;

If we wanna display  a "Hello World" message in a message box  in the

sence , wht we have to do for that ?

I knew one thing , by using frames  and Panel we can do that . But i

need a compact coding for that either that is in simple java , frames

or Panel .

Use JOptionPane...
Usage:Refer the JDK api...