assert keyword (specified in JSR 41)
Regular expressions modeled after Perl regular expressions
Exception chaining allows an exception to encapsulate original lower-level exception
Internet Protocol version 6 (IPv6) support
Non-blocking I/O (named NIO) (specified in JSR 51)
Logging
API (specified in JSR 47)
Image I/O
API for reading and writing images in formats like JPEG and PNG
Integrated XML parser and XSLT processor (JAXP) (specified in JSR 5 and JSR 63)
Integrated security and cryptography extensions (JCE, JSSE, JAAS)
Java Web Start included (Java Web Start was first released in March 2001 for J2SE 1.3) (specified in JSR 56)
Preferences
API (java.util.prefs)
Public support and security updates for Java 1.4 ended in October 2008. Paid security updates for Oracle customers ended in February 2013.