resources.report.rules.pmd.EqualsNull.html Maven / Gradle / Ivy

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EqualsNull


EqualsNull
Inexperienced programmers sometimes confuse comparison concepts
and use equals() to compare to null.
        
		
		
		    
    			This rule is defined by the following XPath expression:
    			
    			
        
//PrimaryExpression
 [
PrimaryPrefix/Name[ends-with(@Image, 'equals')]
or
PrimarySuffix[ends-with(@Image, 'equals')]
]
[PrimarySuffix/Arguments/ArgumentList[count(Expression)=1]
  /Expression/PrimaryExpression/PrimaryPrefix
   /Literal/NullLiteral]
    
                
  
		    
		    
	    
	    
        
        
        Example:
            
                    
       
class Bar {
   void foo() {
       String x = "foo";
       if (x.equals(null)) { // bad!
        doSomething();
       }
   }
}