You see I am using an online software and run into problem and I look into the Java console and found these message. Thought I am new to Java, I have some background on programming in BASIC. I suspect there are some bugs in the program or some problem with the server. When I bring the matter to the vendor, there is no solution so far (already months, they still don't know what is the problem). So I am just want to learn some knowledge about Java. So far, I am satisfied with the answer provide by Suhas Bilaye and I have requested topic as resoved. Thank you for that.