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Avoid Empty Methods in Java

Medium
maintainabilityreadability

What is it?​

This practice is triggered by the presence of empty methods in your Java code, which can be misleading and reduce code readability and maintainability.

Why apply it?​

Empty methods can confuse developers into thinking they implement specific functionality, leading to maintenance and comprehension issues. They should either perform some operation, throw an exception, or include a comment explaining their purpose.

How to fix it?​

Ensure that methods either contain functionality, throw an exception when they aren't implemented, or include a comment confirming the intentional absence of code.

Examples​

Example 1:​

Negative​

The negative example contains empty methods without functionality, exceptions, or explanatory comments.

public class ExampleClass {
    public void process() {
    }

    @Override
    public void notImplemented() {
    }

    @Override
    public void emptyOnPurpose() {
    }
}

Example 2:​

Positive​

The positive example provides functionality within the method or includes a comment explaining why the method is intentionally left empty.

public class ExampleClass {
    public void process() {
        // Method that performs some processing
        System.out.println("Processing...");
    }

    @Override
    public void notImplemented() {
        throw new UnsupportedOperationException("notImplemented() cannot be performed yet");
    }

    @Override
    public void emptyOnPurpose() {
        // Intentionally left blank due to subclass requirements
    }
}

Negative​

The negative example shows an unimplemented method without any explanation or exception throwing.

public class Calculation {
    public double add(double a, double b) {
        return a + b;
    }

    public double notImplementedYet() {
    }
}

Example 3:​

Positive​

The positive example assures the method throws an exception if it's not yet implemented.

public class Calculation {
    public double add(double a, double b) {
        return a + b;  // performs addition
    }

    public double notImplementedYet() {
        throw new UnsupportedOperationException("Feature not yet implemented");
    }
}