Making Eclipse Usable

As a Vim user, I have found it really hard to get back to using Eclipse. For big Java projects, using Eclipse can improve productivity tremendously. Here's what I have done to make Eclipse usable:

• Install Vrapper for Vim bindings
• Update site: http://vrapper.sourceforge.net/update-site/stable
• Install the Eclipse Color Theme Plugin which comes with a great set of default color schemes
• Update site: http://eclipse-color-theme.github.com/update/
• My favorite color scheme so far is Wombat
• Install Maven
• Update site: http://download.eclipse.org/technology/m2e/releases
• Use smaller font sizes for overall appearance on Linux
• Some Eclipse IDE settings:
• Toggle mark occurrences (Alt-Shift-O)
• Enable line number
• Disable line highlighting
• Smaller font sizes for Editor and Console

Sun Java on Ubuntu 12

Sun Java is no longer available on Ubuntu packaging due to licensing issues with Oracle. OpenJDK is provided instead. One solution to this is to use the sun-update-jre package via Dunisoft. However, this did not meet my requirements as the package does not include javac.

My solution was to extract the bin file provided by Sun/Oracle by following the steps here. Do note to fix your symlinks for javadoc, javah and javap.

sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk1.6.0_32/bin/javac 1
sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk1.6.0_32/bin/java 1
sudo update-alternatives --install /usr/bin/javaws javaws /usr/lib/jvm/jdk1.6.0_32/bin/javaws 1
sudo update-alternatives --install /usr/bin/javadoc javadoc /usr/lib/jvm/jdk1.6.0_32/bin/javadoc 1
sudo update-alternatives --install /usr/bin/javah javah /usr/lib/jvm/jdk1.6.0_32/bin/javah 1
sudo update-alternatives --install /usr/bin/javap javap /usr/lib/jvm/jdk1.6.0_32/bin/javap 1

sudo update-alternatives --config javac
sudo update-alternatives --config java
sudo update-alternatives --config javaws
sudo update-alternatives --config javadoc
sudo update-alternatives --config javah
sudo update-alternatives --config javap

Optimizations on ACM Timus

Some tricks I use on http://acm.timus.ru

Note: ACM Timus uses MS VCPP compiler, which differs from g++.

1. c++ is much much more efficient than java.
2. Use short/char instead of int whenever possible (to save memory), esp for arrays. Of course, there is a potential speed / memory trade off here since 4 byte ints register-size, but it doesn't seem to be issue on ACM Timus.
3. When memory is an issue, use stdio instead of iostream.
4. Using iostream may be "faster" than stdio?
5. "Implicit" stack overflow solution:
Use #pragma comment(linker, "/STACK:16777216")
6. Struct packing (for arrays) may not be memory efficient.
7. STL saves coding time.
8. Useful: #define FOR(i,n) for(i=0;i<(n);i++)

Java Optimizations:
1. Many prints are slower than one single print.
2. Buffered Reader/Writer is faster than Scanner.

OOP

Its almost impossible to ignore the entire debate sparked off from a post by Bob Harper of CMU:
First, it was on hacker news, then it was slashdotted with over 600+ comments.

Java Code Coverage for Eclipse

Java coders doing JUnit testing should install this.
http://www.eclemma.org/

A more advanced code coverage tool is Clover, which you can try for [continuous] fully functional 30-day trial.

http://www.atlassian.com/software/clover/

@Override in Java

@Override

Indicates that a method declaration is intended to override a method declaration in a superclass. If a method is annotated with this annotation type but does not override a superclass method, compilers are required to generate an error message.

Tip of the day: The @Override annotation is a useful feature to ensure that you are overriding the correct method. Mostly used in places such as:

@Override
public int hashCode()

@Override
public boolean equals(Object obj)

Java 7

Java 7 JDK: September 2010

Here are 7 of the new features that have been completed:

* Language support for collections
* Automatic Resource Management
* Improved Type Inference for Generic Instance Creation (diamond)
* Underscores in numeric literals
* Strings in switch
* Binary literals
* Simplified Varargs Method Invocation

Read more about the new language features here...

Java 7 (Project Coin) is actually looking good! For a modern programming language to stay relevant, it is important to introduce new paradigms to make programming easier while maintaining a large degree of backward compatibility. It wasn't so long ago that Python made a gigantic leap from 2.6 to 3.0.