Added iteration using iterator, if List is not ArrayList.

Reason for this is that if List is LinkedList, complexity for get(int i) is O(n/4).

jme3-core/src/main/java/com/jme3/material/Material.java

@@ -751,10 +751,12 @@ public class Material implements CloneableSmartAsset, Cloneable, Savable {
 
     private int applyOverrides(Renderer renderer, Shader shader, List<MatParamOverride> overrides, int unit) {
         MatParamOverride override;
+        boolean isArrayList = overrides instanceof ArrayList;
+        Iterator<MatParamOverride> iterator = isArrayList ? null : overrides.iterator();
 
-        // manual iteration is used to avoid iterator allocation and to increase iteration performance
+        // manual iteration is used to avoid iterator allocation and to increase iteration performance in case of ArrayList
         for (int i = 0, listSize = overrides.size(); i < listSize; i++) {
-            override = overrides.get(i);
+            override = isArrayList ? overrides.get(i) : iterator.next();
 
             VarType type = override.getVarType();
 

jme3-core/src/main/java/com/jme3/material/Technique.java

@@ -44,6 +44,7 @@ import com.jme3.shader.VarType;
 import com.jme3.util.ListMap;
 import java.util.ArrayList;
 import java.util.EnumSet;
+import java.util.Iterator;
 import java.util.List;
 
 /**
@@ -112,10 +113,12 @@ public final class Technique {
 
     private void applyOverrides(DefineList defineList, List<MatParamOverride> overrides) {
         MatParamOverride override;
+        boolean isArrayList = overrides instanceof ArrayList;
+        Iterator<MatParamOverride> iterator = isArrayList ? null : overrides.iterator();
 
-        // manual iteration is used to avoid iterator allocation and to increase iteration performance
+        // manual iteration is used to avoid iterator allocation and to increase iteration performance in case of ArrayList
         for (int i = 0, listSize = overrides.size(); i < listSize; i++) {
-            override = overrides.get(i);
+            override = isArrayList ? overrides.get(i) : iterator.next();
 
             if (!override.isEnabled()) {
                 continue;