I totally agree with Sebastian!
In addition; I recommend to write a lot of memory
cards with questions and answers such as "does length() refer to Strings or to Arrays?".
You can take these
cards (I personally have written the huge amount of 700 cards) with you and go them through when you are waiting for the bus (or train), for example.
Concerning writing code, I suggest to do it not only with an
IDE (such as eclipse), but using the good old vi-editor (you can download Cygwin - which acts as a Linux API emulation layer - in order to get the vi-editor, you need to choose it explicitly while installing Cygwin).
Working with the vi-editor helps you a lot to become more secure with coding (at least the very basics) - and you get well prepared for the famous drag & drop questions, as well. Imagine coding something with serialization: do you know by heart with exceptions can be thrown in conjunction with FileOutputStream and ObjectOutputStream? After compiling your files by hand maybe even several times, you finally will! No code completion, no syntax highlighting - it can be very hard at the beginning, but you learn a lot.
(another positive side-effect using vi can arise in a future project - for example, when you are asked to perform server-side trouble-shooting in a pure Unix environment, without any IDE)
Hope this helps!