IntelliJ IDEA
 
2023.2
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Extract field

Last modified: 07 September 2023

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

  2. Press CtrlAlt0F or go to Refactor | Extract Field.

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

    Select an expression

    If IntelliJ IDEA detects more than one occurrence in your code, it lets you specify which occurrences to replace.

    Extract multiple occurrences of a field

    You can press CtrlAlt0F 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.

Before

After

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