i have to download plug in for form designing in java swing..
No you don't. Those form designers only create workable forms when you understand the Java layouts. When you understand the Java layouts, the form designer becomes unnecessary.
For further information see the Creating a GUI With JFC/Swing trail of the Java Tutorial.
..is there any free plug in for from designing
Is that a question? Don't forget to add a question mark (?) to questions. While on the subject, those words are 'I', 'Java' and 'Swing'.
please help me
Please try not to sound so pathetic. You are more likely to get help if you take more care with upper case letters.