Small refactoring.

Author: Michael Haas

compiler/src/jdk.graal.compiler/src/jdk/graal/compiler/hotspot/nodes/InvokeJavaMethodNode.java

@@ -44,7 +44,7 @@
  * state before the {@code acmp}'s pop operation. The call site resolution requires the BCI of the
  * {@code acmp} bytecode.</li>
  * </ul>
- * Compared to an {@link Invoke} node, the node is side-effect free and the call does not originate
+ * Compared to an {@link Invoke} node, the node is side effect free and the call does not originate
  * from the associated bci. The target method must be static and is bound to the call site to
  * override the bytecode based call site resolution.
  */
@@ -77,7 +77,7 @@ public void setTargetMethod(ResolvedJavaMethod targetMethod) {
     @Input protected NodeInputList<ValueNode> arguments;
 
     private int bci;
-    private ResolvedJavaMethod callerMethod;
+    private final ResolvedJavaMethod callerMethod;
     private ResolvedJavaMethod targetMethod;
     private final CallTargetNode.InvokeKind invokeKind;
     private final StampPair returnStamp;