ConstCharacterBase: strengthen the getPhysicsSystem() method

Author: stephengold

src/main/java/com/github/stephengold/joltjni/CharacterRefC.java

@@ -360,8 +360,8 @@ public Vec3 getLinearVelocity(boolean lockBodies) {
      * @return the pre-existing object (not {@code null})
      */
     @Override
-    public ConstPhysicsSystem getPhysicsSystem() {
-        ConstPhysicsSystem result = ptr.getPhysicsSystem();
+    public PhysicsSystem getPhysicsSystem() {
+        PhysicsSystem result = ptr.getPhysicsSystem();
         return result;
     }
 

src/main/java/com/github/stephengold/joltjni/CharacterVirtualRefC.java

@@ -476,8 +476,8 @@ public float getMaxStrength() {
      * @return the pre-existing instance
      */
     @Override
-    public ConstPhysicsSystem getPhysicsSystem() {
-        ConstPhysicsSystem result = ptr.getPhysicsSystem();
+    public PhysicsSystem getPhysicsSystem() {
+        PhysicsSystem result = ptr.getPhysicsSystem();
         return result;
     }
 

src/main/java/com/github/stephengold/joltjni/readonly/ConstCharacterBase.java

@@ -21,6 +21,7 @@ of this software and associated documentation files (the "Software"), to deal
  */
 package com.github.stephengold.joltjni.readonly;
 
+import com.github.stephengold.joltjni.PhysicsSystem;
 import com.github.stephengold.joltjni.RVec3;
 import com.github.stephengold.joltjni.ShapeRefC;
 import com.github.stephengold.joltjni.StateRecorder;
@@ -137,7 +138,7 @@ public interface ConstCharacterBase extends ConstJoltPhysicsObject {
      *
      * @return the pre-existing instance, or {@code null} if none
      */
-    ConstPhysicsSystem getPhysicsSystem();
+    PhysicsSystem getPhysicsSystem();
 
     /**
      * Copy the character's "up" direction. The character is unaffected.