JAVA Versions difference

1) Java 7  (Code named Dolphin and released on July 28, 2011)

• Strings in switch Statement.
• Type Inference for Generic Instance Creation.
• Multiple Exception Handling.
• Support for Dynamic Languages.
• Binary Literals, underscore in literals.
• Automatic null Handling.
• New file I/O library to enhance platform independence and add support for metadata and symbolic links. The new packages are java.nio.file and java.nio.file.attribute.
• Upstream updates to XML and Unicode.

2)  Java 6  (Code named Mustang and released on December 11, 2006)

• Scripting Language Support
• JDBC 4.0 API Support
• Java Compiler API : an API allowing a Java program to select and invoke a Java Compiler programmatically.
• Pluggable Annotations.
• Native PKI, Java GSS, Kerberos and LDAP support.
• Integrated Web Services.
• Lot more enhancements.

3)  Java 5  (Code named Tiger and released on September 30, 2004)

• Generics
• Enhanced for Loop
• Autoboxing/Unboxing
• Typesafe Enums
• Varargs
• Static Import
• Metadata (Annotations)

4)  Java 1.4  (Code named Merlin and released on February 6, 2002)

• XML Processing.
• Java Print Service.
• Logging API.
• Java Web Start.
• JDBC 3.0 API.
• Assertions.
• Preferences API.
• Chained Exception.
• IPv6 Support.
• Regular Expressions.
• Image I/O API.

5)  Java 1.3  (Code named Kestrel and released on May 8, 2000)

• Java Sound
• Jar Indexing
• A huge list of enhancements in almost all the java area.

6)  Java 1.2  (Code named Playground and released on December 8, 1998)

• Collections framework.
• Java String memory map for constants.
• Just In Time (JIT) compiler.
• Jar Signer for signing Java ARchive (JAR) files.
• Policy Tool for granting access to system resources.
• Java Foundation Classes (JFC) which consists of Swing 1.0, Drag and Drop, and Java 2D class libraries.
• Java Plug-in.
• Scrollable result sets, BLOB, CLOB, batch update, user-defined types in JDBC.
• Audio support in Applets.

7)  Java 1.1  (Released on February 19, 1997)

• JDBC (Java Database Connectivity)
• Inner Classes
• Java Beans
• RMI (Remote Method Invocation)
• Reflection (introspection only)

8)  Java 1.0  (Code named Oak and released on January 23, 1996.)