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

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ClassCastExceptionWithToArray


ClassCastExceptionWithToArray
if you need to get an array of a class from your Collection,
you should pass an array of the desidered class
as the parameter of the toArray method. Otherwise you will get a
ClassCastException.
  
		
		
		    
    			This rule is defined by the following XPath expression:
    			
    			
    
//CastExpression[Type/ReferenceType/ClassOrInterfaceType[@Image !=
"Object"]]//PrimaryExpression
[
 PrimaryPrefix/Name[ends-with(@Image, '.toArray')]
 and
 PrimarySuffix/Arguments[count(*) = 0]
and
count(PrimarySuffix) = 1
]

    
  
		    
		    
	    
	    
        
        
        Example:
            
                    

import java.util.ArrayList;
import java.util.Collection;

public class Test {

    public static void main(String[] args) {
        Collection c=new ArrayList();
        Integer obj=new Integer(1);
        c.add(obj);

        // this would trigger the rule (and throw a ClassCastException
if executed)
        Integer[] a=(Integer [])c.toArray();

        // this wouldn't trigger the rule
        Integer[] b=(Integer [])c.toArray(new Integer[c.size()]);
    }
}