New Features in JDK 5, JDK 6, JDK 7, JDK 8, JDK 9, JDK 10, JDK 11

JDK 1.5

- Generics

- Metadata

- Autoboxing and unboxing

- Enumerations

- The swing of JDK1.5 has an all-new look

- Varags

- Enhanced for each loop

- Concurrency utilities


JDK 1.6


- Improved performance(JDK 1.6 is faster )

- JavaScript that is integrated and included in the entire platform

- JDBC4 implementation

- Enhanced web services support(Client and Core Java Architecture for XML-Web Services (JAX-WS) 2.0 APIs)

- API for XML digital signature services for secure web services

- Support for Java Architecture for XML Binding (JAXB) 2.0

- improved security enhancements (Native platform security, Java Authentication and Authorization Service (JAAS), the New Smart Card I/OAPI, native security services)



JDK 7 
(July 2011)

- String in switch
- Improved Type Inference for generics instance creation

From:
Map<String, List<String>> map = new HashMap<String, List<String>>();
To:
Map<String, List<String>> map = new HashMap<>();

- Better Exception Handling (Multiple exceptions handling to eliminate duplication of codes)
Before:

try {

    // execute code that may throw 1 of the 3 exceptions below.

} catch(SQLException e) {
    logger.log(e);

} catch(IOException e) {
    logger.log(e);

} catch(Exception e) {
    logger.severe(e);
}

After:

try {

    // execute code that may throw 1 of the 3 exceptions below.

} catch(SQLException | IOException e) {
    logger.log(e);

} catch(Exception e) {
    logger.severe(e);
}

- Automatic resource management in try-statement
Try with resources:
Before:

BufferedReader br = new BufferedReader(new FileReader(path));
    try {
        return br.readLine();
    } finally {
        if (br != null) br.close();
    }

After:

try (BufferedReader br =
                   new BufferedReader(new FileReader(path))) {
        return br.readLine();
} 

- JDBC enhancement 

JDK8 
(March 2014)

- Language-level support for Lambda Expressions

- PermGen completely removed and replaced with a new space called Metaspace

- New Date and Time API
- Small VM

JDK 9
September 22, 2016

- Jshell = Java + REPL
- G1 will be the new default garbage collector
Http2Client, Java Platform Module System (JPMS),  
Multi-release jar files, Stack Walking API, Private methods in an interface, Process API updates, Collection API updates, Stream API improvements, and etc.
Below are the few differences between Java 8 and Java 9

• In Java 8 and earlier versions, the top-level component is the package. It places a set of related types (classes, interfaces, enums, and etc) into a group, and also contains a set of resources whereas Java 9 introduces a new component: module, which can be used to place a set of related packages into a group, and also another new component: the module descriptor, module-info.java file.
• Java 8 applications use packages as a top-level component whereas Java 9 applications use modules as a top-level component.
• Each Java 9 module has only one module with one module descriptor whereas Java 8 package doesn't build multiple modules into a single module.