Java Integer Class | Methods | Integer Wrapper Class Example

Java integer class is a Wrapper class and comes Under the java.lang.Number package. This class has wraps a value of the primitive type int in an object. Only single fields can contain Integer object with type int.

Integer Compatibility Version: JDK 1.0

 Instantiate Integer Wrapper Class

Here is the simple syntax of use Integer in Java. Using a new keyword with Integer class is no longer with Java 11 Version.

Integer integerValue = 100;

Java integer class example

Here is a code of integer wrapper class in java example. Creating and printing the value and type of.

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

        Integer integerValue = 100;
        System.out.println(integerValue.getClass());
        System.out.println(integerValue);
    }
}

Output: class java.lang.Integer
100

Field of an Integer Object

Here are basic and important fields of Integer class Object.

Java Integer Methods

Here we are mentioning some important methods of use in Integer, for a complete list do follow below official Java document site.

compare(int x, int y): This method simply returns -1 and 0, the result of comparing the two int method argument. Where -1 not equivalent and 0 for equal.

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

        System.out.println(Integer.compare(10,59));
        System.out.println(Integer.compare(10,10));
    }
}

Output: -1
0

compareTo(Integer another integer): A compare the Integer value to passed int value and return an int, if equal then 0 otherwise 1.

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

        Integer a = 100;
        System.out.println(a.compareTo(100));
        System.out.println(a.compareTo(3));
    }
}

Output: 0
1

reverse(int i): Returns the reverse value the order of the bits in the two\’s complement binary representation of the specified int value.

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

        Integer a = 546;
        System.out.println(Integer.reverse(a));
    }
}

Output: 1145044992

For converting an Integer to Sring and other converting methods we will learn later tutorials.

Reference: https://docs.oracle.com/javase/9/docs/api/?java/lang/Integer.html (Official Site)

Note: This example (Project) is developed in IntelliJ IDEA 2018.2.6 (Community Edition)
JRE: 11.0.1
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
macOS 10.14.1

Java version 11

All Java Data Types Examples are in Java 11, so it may change its different from Java 9 or 10 or upgraded versions.