few changes i observed
1. enum keyword
3. var args string ...
4. printf function
5. java.util.concurrent package
6. static imports
7. Addition of stack and queues beside other class in collection interface
8. AutoBoxing and UnBoxing
Padma priya Gururajan wrote:What are the differences between java 1.4 and java 1.5?
Lots, as harshvardhan has shown. Java 1.5 is arguably the most significant release of Java there's ever been; and is certainly the biggest one since Java 1.2.
Generics alone was a big enough change to warrant its own tutorial.
This page contains the major items for all Java releases, and if you read it, you'll see that Java 1.4 has been obsolete since October 2008, and 1.5 since 2009.