Extract field

Last modified: 08 March 2021

The Extract Field refactoring lets you declare a new field and initialize it with the selected expression. The original expression is replaced with the usage of the field.

Extract a field in place

  1. Position the caret within a piece of code you want to extract into a field.

  2. Press Ctrl+Alt+F or from the main menu, select Refactor | Extract Field.

  3. Select an expression you want introduce as a field.

    Extract field
    If IntelliJ IDEA detects more than one occurrence in your code, it lets you specify which occurrences to replace.
    Extract field occurrences
    Extract multiple occurrences of a field
    You can press Ctrl+Alt+F twice to open the Extract Field dialog where you can specify additional details, such as visibility options, or options for initializing your variable.
    Extract field dialog

Example

Let's extract the anotherClass.intValue(); variable into a field. As a result, IntelliJ IDEA changes the selected variable name to number and declares it as the private int number field.

BeforeAfter
public class Class {
    AnotherClass anotherClass;
    public void method() {
        int a = 1;

        int b = a + anotherClass.intValue();
        int c = b + anotherClass.intValue();
    }
}
public class Class {
    public AnotherClass anotherClass;
    private int number;

    public void method() {
        int a = 1;
        number = anotherClass.intValue();
        int b = a + number;
        int c = b + number;
    }
}

See also

Reference