OverridesGuiceInjectableMethod
This method is not annotated with @Inject, but it overrides a method that is annotated with @com.google.inject.Inject. Guice will inject this method, and it is recommended to annotate it explicitly.

Category
GUICE
Severity
WARNING
Maturity

The problem

Unlike with @javax.inject.Inject, if a method overrides a method annotated with @com.google.inject.Inject, Guice will inject it even if it itself is not annotated. This differs from the behavior of methods that override @javax.inject.Inject methods since according to the JSR-330 spec, a method that overrides a method annotated with @javax.inject.Inject will not be injected unless it iself is annotated with @Inject. Because of this difference, it is recommended that you annotate this method explicitly.

Suppression

Suppress false positives by adding an @SuppressWarnings("OverridesGuiceInjectableMethod") annotation to the enclosing element.


Positive examples

OverridesGuiceInjectableMethodPositiveCases.java

/*
 * Copyright 2013 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.errorprone.bugpatterns.inject.guice.testdata;

/**
 * @author sgoldfeder@google.com (Steven Goldfeder)
 */
public class OverridesGuiceInjectableMethodPositiveCases {

  /**
   * Class with a method foo() annotated with @com.google.inject.Inject.
   */
  public class TestClass1 {
    @com.google.inject.Inject
    public void foo() {}
  }

  /**
   * Class with a method foo() that is not annotated with @Inject, but overrides a method that is
   * annotated with @com.google.inject.Inject
   */
  public class TestClass2 extends TestClass1 {
    // BUG: Diagnostic contains: @Inject
    public void foo() {}
  }

  /**
   * Class with a method foo() that is not annotated with @Inject, but overrides a method that in
   * turn is overrides a method that is annotated with @com.google.inject.Inject
   */
  public class TestClass3 extends TestClass2 {
    // BUG: Diagnostic contains: @Inject
    public void foo() {}
  }

  /**
   * Class with a method foo() that is not annotated with @javax.inject.Inject and overrides a
   * method that is annotated with @com.google.inject.Inject. This class does not contain an error,
   * but it is extended in the next test class.
   */
  public class TestClass4 extends TestClass1 {
    @javax.inject.Inject
    public void foo() {}
  }

  /**
   * Class with a method foo() that is not annotated with @Inject and overrides a method that is is
   * annotated with @javax.inject.Inject. This super method in turn overrides a method that is
   * annoatated with @com.google.inject.Inject.
   */
  public class TestClass5 extends TestClass4 {
    // BUG: Diagnostic contains: @Inject
    public void foo() {}
  }

  /** Class that extends a class with an injected method, but doesn't override it. */
  public class TestClass6 extends TestClass1 {}

  /**
   * Class that extends a class with an injected method, but it was declared in a supertype that
   * isn't a direct supertype.
   */
  public class TestClass7 extends TestClass1 {
    // BUG: Diagnostic contains: @Inject
    public void foo() {}
  }
}

Negative examples

OverridesGuiceInjectableMethodNegativeCases.java

/*
 * Copyright 2013 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.errorprone.bugpatterns.inject.guice.testdata;

/**
 * @author sgoldfeder@google.com (Steven Goldfeder)
 */
public class OverridesGuiceInjectableMethodNegativeCases {

  /**
   * Class with a method foo() annotated with @com.google.inject.Inject.
   */
  public class TestClass1 {
    @com.google.inject.Inject
    public void foo() {}
  }
  
  /**
   * Class with a method foo() annotated with @javax.inject.Inject.
   */
  public class TestClass2 {
    @javax.inject.Inject
    public void foo() {}
  }
  
  /**
   * Class with a method foo() annotated with @javax.inject.Inject that overrides a method 
   * annotated with @com.google.inject.Inject.
   */
  public class TestClass3 extends TestClass1 {
    @javax.inject.Inject
    public void foo() {}
  }
  
  /**
   * Class with a method foo() annotated with @com.google.inject.Inject that overrides a method
   * annoted with @javax.inject.Inject.
   */
  public class TestClass4 extends TestClass2 {
    @com.google.inject.Inject
    public void foo() {}
  }
 
  /**
   * Class with a method foo() annotated with @javax.inject.Inject that overrides a method
   * annotated with @com.google.inject.Inject
   */
  public class TestClass5 extends TestClass1 {
    @javax.inject.Inject
    public void foo() {}
  }
  
  /**
   * Class with a method foo() that is not annotated with @Inject, but overrides a method that is
   * annotated with @com.google.inject.Inject. Warning is suppressed.
   */
  public class TestClass6 extends TestClass1 {
    @SuppressWarnings("OverridesGuiceInjectableMethod")
    @Override 
    public void foo() {}
  }

  /** Class that extends a class with an injected method, but doesn't override it. */
  public class TestClass7 extends TestClass1 {}
}