Java long keyword

The Java long keyword is a primitive data type. It is used to declare variables. It can also be used with methods. It can hold a 64-bit two's complement integer.

Points to remember

The long contains minimum value of -2⁶³ and a maximum value of 2⁶³-1.
From Java 8, the long can represent as an unsigned 64-bit long, which has a minimum value of 0 and a maximum value of 2⁶⁴-1
Its default value is 0L.
Its default size is 8 byte.
It is used when you need a higher range integer value.

Examples of Java long keyword

Example 1

Let's see an example to use long data type with positive and negative value.

public class LongExample1
{
public static void main(String...k)
{
long num1=10L;
long num2=-10L;
System.out.println("num1: "+num1);
System.out.println("num2: "+num2);
}
}

Output:

num1: 10
num2: -10

Example 2

Let's see an example to check whether the long data type holds decimal value.

public classLongExample2
{
public static void main(String...k)
{
long num=10.5;
System.out.println("num: "+num);
}
}

Output:

error: incompatible types: possible lossy conversion from double to long

Example 3

Let's see an example to check whether the long data type holds float value.

public class LongExample3
{
public static void main(String...k)
{
long num=10f;
System.out.println("num: "+num);
}
}

Output:

error: incompatible types: possible lossy conversion from float to long

Example 4

Let's see an example to check whether the long data type holds char value. In such case, the compiler typecast the character implicitly to long type and returns the corresponding ASCII value.

public class LongExample4
{
public static void main(String...k)
{
long num='a';
System.out.println("num: "+num);
}	
}

Output:

num: 97

Example 5

In this example, long data type holds the minimum and maximum value.

public class LongExample5
{
public static void main(String...k)
{
long min=-9223372036854775808L;
        long max=9223372036854775807L;
        System.out.println("min: "+min);
        System.out.println("max: "+max);
}
}

Output:

min: -9223372036854775808
max: 9223372036854775807

Example 6

Let's create a method that returns a long type value.

public class LongExample6 {

	public long display()
	{	
		return 10L;
	}
	
	public static void main(String[] args) {
		
		LongExample6 obj=new LongExample6();
		System.out.println(obj.display());
	}
	
}

Output:

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