Fix wrong implementation of hasImageEqualTo

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/AbstractNode.java

@@ -7,6 +7,7 @@ package net.sourceforge.pmd.lang.ast;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Objects;
 import java.util.logging.Logger;
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
@@ -134,7 +135,7 @@ public abstract class AbstractNode implements Node {
 
     @Override
     public boolean hasImageEqualTo(String image) {
-        return this.getImage() != null && this.getImage().equals(image);
+        return Objects.equals(this.image, image);
     }
 
     @Override

pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/Node.java

@@ -90,10 +90,20 @@ public interface Node {
 
     int jjtGetId();
 
+
+    /**
+     * Returns a string token, usually filled-in by the parser, which describes some textual
+     * characteristic of this node. This is usually an identifier.
+     */
     String getImage();
 
     void setImage(String image);
 
+    /**
+     * Returns true if this node's image is equal to the given string.
+     *
+     * @param image The image to check
+     */
     boolean hasImageEqualTo(String image);
 
     int getBeginLine();