Package getImplementationVersion() method in Java with Examples

The getImplementationVersion() method of java.lang.Package class is used to get the version of the implementation of this package. The method returns the implementation version of the package as a String.
Syntax:

public String getImplementationVersion()

Parameter: This method does not accept any parameter.
Return Value: This method returns the implementation version of the package as a String, if known. Else it returns null
Below programs demonstrate the getImplementationVersion() method.
Example 1:

Java

// Java program to demonstrate
// getImplementationVersion() method

public class Test {
    public static void main(String[] args)
    {

        // returns the Package object
        // for this package
        Package myPackage
            = Package.getPackage("java.lang");

        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());

        // Get the implementation version of myPackage
        // using getImplementationVersion() method
        System.out.println(
            "Implementation version of myPackage: "
            + myPackage.getImplementationVersion());
    }
}

Output:

Package represented by myPackage: package java.lang, Java Platform API Specification, version 1.8
Implementation version of myPackage: 1.8.0_181

Example 2:

Java

// Java program to demonstrate
// getImplementationVersion() method

public class Test {
    public static void main(String[] args)
    {

        // returns the Package object
        // for this package
        Package myPackage
            = Package.getPackage("java.io");

        System.out.println(
            "Package represented by myPackage: "
            + myPackage.toString());

        // Get the name of myPackage
        // using getImplementationVersion() method
        System.out.println(
            "Implementation version of myPackage: "
            + myPackage.getImplementationVersion());
    }
}

Output:

Package represented by myPackage: package java.io, Java Platform API Specification, version 1.8
Implementation version of myPackage: 1.8.0_181

Reference: https://docs.oracle.com/javase/9/docs/api/java/lang/Package.html#getImplementationVersion–