Double decimal formatting in Java

I'm having some problems formatting the decimals of a double. If I have a double value, e.g. 4.0, how do I format the decimals so that it's 4.00 instead?

One of the way would be using NumberFormat.

NumberFormat formatter = new DecimalFormat("#0.00");     
System.out.println(formatter.format(4.0));

Output:

4.00

With Java 8, you can use format method..: -

System.out.format("%.2f", 4.0); // OR

System.out.printf("%.2f", 4.0); 

• f is used for floating point value..
• 2 after decimal denotes, number of decimal places after .

For most Java versions, you can use DecimalFormat: -

    DecimalFormat formatter = new DecimalFormat("#0.00");
    double d = 4.0;
    System.out.println(formatter.format(d));

Use String.format:

String.format("%.2f", 4.52135);

As per docs:

The locale always used is the one returned by Locale.getDefault().

Using String.format, you can do this:

double price = 52000;
String.format("$%,.2f", price);

Notice the comma which makes this different from @Vincent's answer

Output:

$52,000.00

A good resource for formatting is the official java page on the subject