Java Convert Decimal to Binary

Let's see the simple example of converting decimal to binary in java.

public class DecimalToBinaryExample1{  
public static void main(String args[]){  
System.out.println(Integer.toBinaryString(10));  
System.out.println(Integer.toBinaryString(21));  
System.out.println(Integer.toBinaryString(31));  
}}  

Output:

1010
10101
11111

Java Decimal to Binary conversion: Custom Logic

We can convert decimal to binary in java using custom logic.

public class DecimalToBinaryExample2{    
public static void toBinary(int decimal){    
     int binary[] = new int[40];    
     int index = 0;    
     while(decimal > 0){    
       binary[index++] = decimal%2;    
       decimal = decimal/2;    
     }    
     for(int i = index-1;i >= 0;i--){    
       System.out.print(binary[i]);    
     }    
System.out.println();//new line  
}    
public static void main(String args[]){      
System.out.println("Decimal of 10 is: ");  
toBinary(10);    
System.out.println("Decimal of 21 is: ");  
toBinary(21);    
System.out.println("Decimal of 31 is: ");    
toBinary(31);  
}}    

Output:

Decimal of 10 is: 
1010
Decimal of 21 is: 
10101
Decimal of 31 is: 
11111