java decimal to binary conversion code example

Example 1: int to binary java

String binary = Integer.toBinaryString(num);

Example 2: java int to binary

public static String makeBinaryString(int n) {
	StringBuilder sb = new StringBuilder();
	while (n > 0) {
    sb.append(n % 2);
		n /= 2;
	}
  	sb.reverse();  	
  	return sb.toString();
}

Example 3: convert decimal to binary in java

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);  
}}