EmptyIf
Empty statement after if

Category
Severity
ERROR
Maturity

Alternate names: empty

The problem

An if statement contains an empty statement as the then clause. A semicolon may have been inserted by accident.

Suppression

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


Positive examples

EmptyIfStatementPositiveCases.java

/*
* Copyright 2011 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.testdata;

/**
* Positive test cases for the empty if statement check.
*
* @author eaftan@google.com (Eddie Aftandilian)
*/

public class EmptyIfStatementPositiveCases {

public static void positiveCase1() {
int i = 10;
// BUG: Diagnostic contains: if (i == 10) {
if (i == 10); {
i++;
}
}

public static void positiveCase2() {
int i = 10;
// BUG: Diagnostic contains: if (i == 10)
if (i == 10);
i++;
System.out.println("foo");
}

public static void positiveCase3() {
int i = 10;
if (i == 10)
// BUG: Diagnostic contains: remove this line
;
i++;
System.out.println("foo");
}

public static void positiveCase4() {
int i = 10;
// BUG: Diagnostic contains: remove this line
if (i == 10) ;
}

public static void positiveCase5() {
int i = 10;
if (i == 10)
// BUG: Diagnostic contains: remove this line
;
{
System.out.println("foo");
}
}
}

Negative examples

EmptyIfStatementNegativeCases.java

/*
* Copyright 2011 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.testdata;
/** @author eaftan@google.com (Eddie Aftandilian) */
public class EmptyIfStatementNegativeCases {

// just a normal use of if
public static void negativeCase1() {
int i = 10;
if (i == 10) {
System.out.println("foo");
}
i++;
}

// empty then part but nonempty else
public static void negativeCase2() {
int i = 0;
if (i == 10) ;
else System.out.println("not 10");
}

// multipart if with non-empty else
public static void negativeCase3() {
int i = 0;
if (i == 10) ;
else if (i == 11) ;
else if (i == 12) ;
else System.out.println("not 10, 11, or 12");
}
}