Java Problem: java.lang.NoSuchMethodError

I was doing a project to implement TCP over UDP. I used makefile to compile these java files easily.

After editing and compiling several times, the Server became unavailable in terminal. It shows just like below.

However, it works well in Eclipse. I tried it in ubuntu and it also works.

I have no idea about this problem. But suddenly when I tried “make clean”, which deletes all .class files in the folder and compile all files again, it works.

Maybe there are some wrong in the old .class files. The most effective way to solve this unusually problem may be delete all compiled files and do compilation again.