java convert binary to decimal

1System.out.println(Integer.parseInt("1010",2));  

1import java.util.Scanner;
2public class BinaryToDecimalDemo 
3{
4   public static void main(String[] args) 
5   {
6      int number, decimal = 0, a = 0;
7      Scanner sc = new Scanner(System.in);
8      System.out.println("Please enter binary number: ");
9      String strBinary = sc.nextLine();
10      number = Integer.parseInt(strBinary);
11      while(number != 0){
12         decimal += (number % 10) * Math.pow(2, a);
13         number = number / 10;
14         a++;
15      }
16      System.out.println("Decimal number: " + decimal);
17      sc.close();
18   }
19}

1public class DecimalToBinaryExample2{    
2public static void toBinary(int decimal){    
3     int binary[] = new int[40];    
4     int index = 0;    
5     while(decimal > 0){    
6       binary[index++] = decimal%2;    
7       decimal = decimal/2;    
8     }    
9     for(int i = index-1;i >= 0;i--){    
10       System.out.print(binary[i]);    
11     }    
12System.out.println();//new line  
13}    
14public static void main(String args[]){      
15System.out.println("Decimal of 10 is: ");  
16toBinary(10);    
17System.out.println("Decimal of 21 is: ");  
18toBinary(21);    
19System.out.println("Decimal of 31 is: ");    
20toBinary(31);  
21}}    

1public class Details {
2 
3  public int BinaryToDecimal(int binaryNumber){
4 
5    int decimal = 0;
6    int p = 0;
7    while(true){
8      if(binaryNumber == 0){
9        break;
10      } else {
11          int temp = binaryNumber%10;
12          decimal += temp*Math.pow(2, p);
13          binaryNumber = binaryNumber/10;
14          p++;
15       }
16    }
17    return decimal;
18  }
19 
20  public static void main(String args[]){
21    Details obj = new Details();
22    System.out.println("110 --> "+obj.BinaryToDecimal(110));
23    System.out.println("1101 --> "+obj.BinaryToDecimal(1101));
24    System.out.println("100 --> "+obj.BinaryToDecimal(100));
25    System.out.println("110111 --> "+obj.BinaryToDecimal(110111));
26  }
27}

1int foo = Integer.parseInt("1001", 2); // 2 is the radix

1import java.util.Scanner;
2class BinaryToDecimal {
3    public static void main(String args[]){
4       Scanner input = new Scanner( System.in );
5       System.out.print("Enter a binary number: ");
6       String binaryString =input.nextLine();
7       System.out.println("Output: "+Integer.parseInt(binaryString,2));
8    }
9}