diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Algebra.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Algebra.java
index b45816e95..482642c19 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Algebra.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Algebra.java
@@ -561,15 +561,15 @@ private static void calculateNumeratorGCD(IExpr arg, int position, IASTAppendabl
      */
     private static Optional<IExpr[]> cancelPlusIntegerGCD(IAST numeratorPlus,
         IInteger denominator) {
-      IASTAppendable plus = numeratorPlus.copyAppendable();
-      IASTAppendable gcd = F.ast(S.GCD, plus.size() + 1);
+      IASTAppendable gcd = F.ast(S.GCD, numeratorPlus.size() + 1);
       gcd.append(denominator);
-      boolean evaled = !plus.exists((IExpr x) -> collectGCDFactors(x, gcd));
+      boolean evaled = !numeratorPlus.exists((IExpr x) -> collectGCDFactors(x, gcd));
       if (evaled) {
         // GCD() has attribute Orderless, so the arguments will
         // be sorted by evaluation!
         IExpr igcd = F.eval(gcd);
         if (igcd.isInteger() && !igcd.isOne()) {
+          IASTAppendable plus = numeratorPlus.copyAppendable();
           return calculatePlusIntegerGCD(plus, denominator, (IInteger) igcd);
         }
       }
@@ -615,7 +615,7 @@ private static IExpr cancelPowerTimes(IExpr powerTimesAST, EvalEngine engine)
         IExpr p10 = parts.get()[1];
         IExpr p11 = F.C1;
         if (p00.isPlus()) {
-          IAST numParts = ((IAST) p00).partitionPlus(x -> isPolynomial(x), F.C0, F.C1, S.List);
+          IAST numParts = p00.partitionPlus(x -> isPolynomial(x), F.C0, F.C1, S.List);
           if (numParts.isPresent() && !numParts.arg1().isOne()) {
             p00 = numParts.arg1();
             p01 = numParts.arg2();
@@ -623,7 +623,7 @@ private static IExpr cancelPowerTimes(IExpr powerTimesAST, EvalEngine engine)
         }
 
         if (p10.isPlus()) {
-          IAST denParts = ((IAST) p10).partitionPlus(x -> isPolynomial(x), F.C0, F.C1, S.List);
+          IAST denParts = p10.partitionPlus(x -> isPolynomial(x), F.C0, F.C1, S.List);
           if (denParts.isPresent() && !denParts.arg1().isOne()) {
             p10 = denParts.arg1();
             p11 = denParts.arg2();
@@ -918,8 +918,9 @@ private IExpr collectSingleVariableRecursive(IExpr expr, IExpr x, final IAST lis
           // "rest" variable
           IPatternSequence blankNullRest =
               F.$ps(F.Dummy("§rest§" + EvalEngine.incModuleCounter()), true);
-          IASTAppendable newLHS = ((IAST) x).copyAppendable();
-          newLHS.append(blankNullRest);
+          IASTAppendable newLHS = ((IAST) x).appendClone(blankNullRest);
+          // newLHS.append(blankNullRest);
+
           final IPatternMatcher matcher = engine.evalPatternMatcher(newLHS);
 
           collectTimesToMap(x, poly, matcher, defaultdict, rest, blankNullRest);
@@ -1271,8 +1272,8 @@ public void distributePositionRecursive(IASTAppendable stepResult, int position)
       }
 
       private void distributeStep(IExpr x, IAST stepResult, int position) {
-        IASTAppendable res2 = stepResult.copyAppendable();
-        res2.append(x);
+        IASTAppendable res2 = stepResult.appendClone(x);
+        // res2.append(x);
         distributePositionRecursive(res2, position + 1);
       }
     }
@@ -4233,7 +4234,7 @@ public IExpr evaluate(final IAST ast, EvalEngine engine) {
         }
         if (arg1.isAST()) {
           ToRadicalsVisitor visitor = new ToRadicalsVisitor(ast);
-          temp = ((IAST) arg1).accept(visitor);
+          temp = arg1.accept(visitor);
           if (temp.isPresent()) {
             return temp;
           }
@@ -5012,9 +5013,8 @@ public static IExpr cancelFractionalParts(IExpr powerTimesAST) throws JASConvers
       }
 
       if (numerator.isPlus() && denominator.isPlus()) {
-        IAST numParts = ((IAST) numerator).partitionPlus(x -> isPolynomial(x), F.C0, F.C1, S.List);
-        IAST denParts =
-            ((IAST) denominator).partitionPlus(x -> isPolynomial(x), F.C0, F.C1, S.List);
+        IAST numParts = numerator.partitionPlus(x -> isPolynomial(x), F.C0, F.C1, S.List);
+        IAST denParts = denominator.partitionPlus(x -> isPolynomial(x), F.C0, F.C1, S.List);
         if (denParts.isPresent() && !denParts.arg1().isOne()) {
           Optional<IExpr[]> result = cancelGCD(numParts.arg1(), denParts.arg1());
           if (result.isPresent()) {
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Arithmetic.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Arithmetic.java
index 940eda551..bae606942 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Arithmetic.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Arithmetic.java
@@ -3613,7 +3613,7 @@ public static IExpr binaryOperator(IAST ast, final IExpr base, final IExpr expon
                 IExpr x = ((IAST) base).arg1();
                 IExpr mNeg = exponent.negate();
                 boolean disabledTrigRules = engine.isDisabledTrigRules();
-                int id = ((IAST) base).headID();
+                int id = base.headID();
                 switch (id) {
                   case ID.Tan:
                     // Tan(x_)^m_?(IntegerQ(#)&&#<0 &):=Cot(x)^(-m),
@@ -4153,7 +4153,7 @@ private static IExpr powerRealBaseOrRealExponent(final IExpr base, final IExpr e
             }
             try {
               long n = ((IInteger) exponent).toLong();
-              return ((INumber) base).power(n);
+              return base.power(n);
             } catch (ArithmeticException ae) {
 
             }
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/BooleanFunctions.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/BooleanFunctions.java
index 0ffa68386..7d5326b50 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/BooleanFunctions.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/BooleanFunctions.java
@@ -2242,15 +2242,14 @@ public IExpr evaluate(IAST ast, EvalEngine engine) {
       }
       boolean evaled = false;
 
-      IASTAppendable result = astEvaled.copyAppendable();
       IExpr.COMPARE_TERNARY[] cResult = new IExpr.COMPARE_TERNARY[astEvaled.size()];
       cResult[0] = IExpr.COMPARE_TERNARY.TRUE;
       for (int i = 1; i < astEvaled.argSize(); i++) {
-        IExpr arg = result.get(i);
+        IExpr arg = astEvaled.get(i);
         if (arg.equals(S.Undefined)) {
           return S.Undefined;
         }
-        final IExpr.COMPARE_TERNARY b = prepareCompare(arg, result.get(i + 1), engine);
+        final IExpr.COMPARE_TERNARY b = prepareCompare(arg, astEvaled.get(i + 1), engine);
         if (b == IExpr.COMPARE_TERNARY.FALSE) {
           return S.False;
         }
@@ -2266,6 +2265,7 @@ public IExpr evaluate(IAST ast, EvalEngine engine) {
       }
       int i = 2;
       evaled = false;
+      IASTAppendable result = astEvaled.copyAppendable();
       for (int j = 1; j < astEvaled.size(); j++) {
         if (cResult[j - 1] == IExpr.COMPARE_TERNARY.TRUE
             && cResult[j] == IExpr.COMPARE_TERNARY.TRUE) {
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Combinatoric.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Combinatoric.java
index e930624f3..429a8d335 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Combinatoric.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/Combinatoric.java
@@ -157,8 +157,8 @@ public synchronized IAST next() {
         if (empty) {
           throw new RuntimeException("invalid call of next()");
         }
-        // IAST res = (IAST) current.clone();
-        IAST res = current.copyAppendable();
+
+        final IAST res = current.copy();
         // search iterator which hasNext
         int i = compit.size() - 1;
         for (; i >= 0; i--) {
@@ -2687,10 +2687,9 @@ private static void tuples(final IAST originalList, final int n, IASTAppendable
             RecursionLimitExceeded.throwIt(counter, ast);
           }
         }
-        IASTAppendable temp;
         for (int j = 1; j < originalList.size(); j++) {
-          temp = subResult.copyAppendable();
-          temp.append(originalList.get(j));
+          IASTAppendable temp = subResult.appendClone(originalList.get(j));
+          // temp.append(originalList.get(j));
           tuples(originalList, n - 1, result, temp, ast, engine);
         }
       } finally {
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/ListFunctions.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/ListFunctions.java
index 3c7c22b28..570b545cd 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/ListFunctions.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/ListFunctions.java
@@ -984,7 +984,7 @@ public MultipleArrayFunction(final EvalEngine engine, final IAST headAST) {
 
       @Override
       public IExpr evaluate(final ISymbol[] variables, final IExpr[] index) {
-        final IASTAppendable ast = fHeadAST.copyAppendable();
+        final IASTAppendable ast = fHeadAST.copyAppendable(index.length);
         return fEngine.evaluate(ast.appendArgs(0, index.length, i -> index[i]));
       }
     }
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/ManipulateFunction.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/ManipulateFunction.java
index e36a6b6c4..16ad1675d 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/ManipulateFunction.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/ManipulateFunction.java
@@ -674,7 +674,7 @@ private static void setBoxRatios(StringBuilder graphicControl, double[] rangeXY)
     private static IExpr sliderWithFormulas(IExpr formula, IAST sliderRange, EvalEngine engine) {
       JavaScriptFormFactory toJS =
           new JavaScriptFormFactory(true, false, -1, -1, JavaScriptFormFactory.USE_MATHCELL);
-      IASTAppendable newsliderRange = sliderRange.copyAppendable();
+      IASTAppendable newsliderRange = sliderRange.copyAppendable(1);
       double stepValue = 1.0;
       double minValue = sliderRange.arg2().evalf();
       double maxValue = sliderRange.arg3().evalf();
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/OutputFunctions.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/OutputFunctions.java
index 5dcb808c4..43cea6c17 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/OutputFunctions.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/OutputFunctions.java
@@ -584,8 +584,7 @@ public IExpr evaluate(final IAST ast, EvalEngine engine) {
         }
         IExpr arg1 = ast.arg1();
         if (arg1.isFunctionID(ID.Plot, ID.ParametricPlot, ID.ParametricPlot)) {
-          IASTAppendable temp = ((IAST) arg1).copyAppendable();
-          temp.append(F.Rule(S.JSForm, S.True));
+          IASTAppendable temp = ((IAST) arg1).appendClone(F.Rule(S.JSForm, S.True));
           arg1 = temp;
         }
         arg1 = engine.evaluate(arg1);
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/SeriesFunctions.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/SeriesFunctions.java
index 2575d7529..468b1a925 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/SeriesFunctions.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/SeriesFunctions.java
@@ -974,7 +974,7 @@ private static IExpr powerLimit(final IAST powerAST, LimitData data, EvalEngine
           }
         }
         if (base.isTimes()) {
-          IAST isFreeResult = ((IAST) base).partitionTimes(x -> x.isFree(data.variable(), true),
+          IAST isFreeResult = base.partitionTimes(x -> x.isFree(data.variable(), true),
               F.C1, F.C1, S.List);
           if (!isFreeResult.arg2().isOne()) {
             return F.Times(F.Power(isFreeResult.arg1(), exponent),
@@ -1886,7 +1886,7 @@ public static IExpr polynomialSeriesCoefficient(IExpr univariatePolynomial, IExp
           }
         }
         for (int i = 1; i < rest.size(); i++) {
-          IASTAppendable term = seriesTemplate.copyAppendable();
+          IASTMutable term = seriesTemplate.copy();
           term.set(1, rest.get(i));
           coefficientPlus.append(term);
         }
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/StructureFunctions.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/StructureFunctions.java
index e39e438b4..1b9ffc627 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/StructureFunctions.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/builtin/StructureFunctions.java
@@ -191,7 +191,7 @@ public IExpr evaluate(IAST ast, EvalEngine engine) {
       if (ast.argSize() < 2 || ast.argSize() > 4) {
         return Errors.printArgMessage(ast, ARGS_2_4, engine);
       }
-      IASTAppendable evaledAST = ast.copyAppendable();
+      IASTMutable evaledAST = ast.copy();
       evaledAST.setArgs(evaledAST.size(), (int i) -> engine.evaluate(evaledAST.get(i)));
 
       int lastIndex = evaledAST.argSize();
@@ -575,7 +575,7 @@ public IExpr evaluate(IAST ast, EvalEngine engine) {
         int[] positions = null;
         if (arg2.isInteger()) {
           positions = new int[1];
-          positions[0] = ((IInteger) arg2).toIntDefault();
+          positions[0] = arg2.toIntDefault();
           if (positions[0] == Integer.MIN_VALUE) {
             return F.NIL;
           }
@@ -2211,7 +2211,7 @@ public static IAST threadList(final IAST list, IExpr head, IExpr mapHead) {
       int listLength = -1;
 
       for (int i = 1; i < list.size(); i++) {
-        if ((list.get(i).isAST()) && (((IAST) list.get(i)).head().equals(head))) {
+        if ((list.get(i).isAST()) && (list.get(i).head().equals(head))) {
           if (listLength == -1) {
             listLength = ((IAST) list.get(i)).argSize();
           } else {
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/combinatoric/KPartitionsList.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/combinatoric/KPartitionsList.java
index b9ae0471c..4cc52a61a 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/combinatoric/KPartitionsList.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/combinatoric/KPartitionsList.java
@@ -36,10 +36,9 @@ public IAST next() {
         return null;
       }
       IASTAppendable part = fResultList.copyAppendable();
-      IASTAppendable temp;
       int j = 0;
       for (int i = 1; i < partitionsIndex.length; i++) {
-        temp = fResultList.copyAppendable();
+        IASTAppendable temp = fResultList.copyAppendable();
         for (int m = j; m < partitionsIndex[i]; m++) {
           temp.append(fList.get(m + fOffset));
         }
@@ -47,7 +46,7 @@ public IAST next() {
         part.append(temp);
       }
 
-      temp = fResultList.copyAppendable();
+      IASTAppendable temp = fResultList.copyAppendable();
       int n = fList.size() - fOffset;
       for (int m = j; m < n; m++) {
         temp.append(fList.get(m + fOffset));
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/eval/interfaces/AbstractFunctionEvaluator.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/eval/interfaces/AbstractFunctionEvaluator.java
index 0ca552f6d..2c6845032 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/eval/interfaces/AbstractFunctionEvaluator.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/eval/interfaces/AbstractFunctionEvaluator.java
@@ -173,7 +173,7 @@ public static IExpr extractImaginaryUnit(final IExpr expression) {
    */
   public static IExpr extractImaginaryUnit(final IExpr expression, boolean checkTimes) {
     if (expression.isNumber()) {
-      if (((INumber) expression).isImaginaryUnit()) {
+      if (expression.isImaginaryUnit()) {
         return F.C1;
       }
       if ((expression.isComplex() || expression.isComplexNumeric())//
@@ -186,7 +186,7 @@ public static IExpr extractImaginaryUnit(final IExpr expression, boolean checkTi
           IAST timesAST = ((IAST) expression);
           IExpr arg1 = timesAST.arg1();
           if (arg1.isNumber()) {
-            if (((INumber) arg1).isImaginaryUnit()) {
+            if (arg1.isImaginaryUnit()) {
               return timesAST.rest().oneIdentity1();
             }
             if ((arg1.isComplex() || arg1.isComplexNumeric())//
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/expression/AbstractAST.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/expression/AbstractAST.java
index e296e3842..73489fe71 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/expression/AbstractAST.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/expression/AbstractAST.java
@@ -1466,7 +1466,7 @@ public final IAST addEvalFlags(final int i) {
   /** {@inheritDoc} */
   @Override
   public IASTAppendable appendAtClone(int position, IExpr expr) {
-    IASTAppendable ast = copyAppendable();
+    IASTAppendable ast = copyAppendable(1);
     ast.append(position, expr);
     return ast;
   }
@@ -5172,7 +5172,11 @@ public IAST map(final Function<IExpr, ? extends IExpr> function, final int start
       temp = function.apply(get(i));
       if (temp.isPresent()) {
         // something was evaluated - return a new IAST:
-        result = copyAppendable();
+        if (i > 1) {
+          result = copy();
+        } else {
+          result = copyAppendable();
+        }
         result.set(i++, temp);
         break;
       }
@@ -5216,7 +5220,11 @@ public IAST mapLeaf(IExpr testHead, final Function<IExpr, IExpr> function,
     }
     if (temp.isPresent()) {
       // something was evaluated - return a new IAST:
-      result = copyAppendable();
+      if (i > 0) {
+        result = copy();
+      } else {
+        result = copyAppendable();
+      }
       result.set(i++, temp);
     }
     if (result.isPresent()) {
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/generic/Predicates.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/generic/Predicates.java
index a1c0171b4..31b885b7e 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/generic/Predicates.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/generic/Predicates.java
@@ -302,8 +302,7 @@ public static Predicate<IExpr> toFreeQ(IExpr pattern) {
     if (pattern.isOrderlessAST() && pattern.isFreeOfPatterns()) {
       // append a BlankNullSequence[] to match the parts of an Orderless expression
       IPatternSequence blankNullRest = F.$ps(null, true);
-      IASTAppendable newPattern = ((IAST) pattern).copyAppendable();
-      newPattern.append(blankNullRest);
+      IASTAppendable newPattern = ((IAST) pattern).appendClone(blankNullRest);
       matcher = new PatternMatcher(newPattern);
     } else {
       matcher = new PatternMatcher(pattern);
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/patternmatching/Matcher.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/patternmatching/Matcher.java
index a755f7782..194a1262a 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/patternmatching/Matcher.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/patternmatching/Matcher.java
@@ -10,7 +10,6 @@
 import org.matheclipse.core.expression.F;
 import org.matheclipse.core.expression.S;
 import org.matheclipse.core.interfaces.IAST;
-import org.matheclipse.core.interfaces.IASTAppendable;
 import org.matheclipse.core.interfaces.IASTMutable;
 import org.matheclipse.core.interfaces.IExpr;
 import org.matheclipse.core.interfaces.IPattern;
@@ -51,13 +50,13 @@ public IExpr visit(IASTMutable ast) {
           return temp;
         }
       }
-      IASTAppendable result = F.NIL;
+      IASTMutable result = F.NIL;
       int i = 1;
       while (i < list.size()) {
         temp = list.get(i).accept(this);
         if (temp.isPresent()) {
           // something was evaluated - return a new IAST:
-          result = list.copyAppendable();
+          result = list.copy();
           result.set(i++, temp);
           break;
         }
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/polynomials/longexponent/ExprPolynomialRing.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/polynomials/longexponent/ExprPolynomialRing.java
index 77d4d68d1..8f4acb2e1 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/polynomials/longexponent/ExprPolynomialRing.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/polynomials/longexponent/ExprPolynomialRing.java
@@ -312,7 +312,7 @@ public ExprPolynomialRing(ExprRingFactory cf, IAST listOfVariables, int n, ExprT
     nvar = n;
     tord = t;
     partial = false; 
-    vars = listOfVariables.copyAppendable();
+    vars = listOfVariables.copy();
     ZERO = new ExprPolynomial(this);
     IExpr coeff = coFac.getONE();
     evzero = new ExpVectorLong(nvar);
@@ -910,7 +910,7 @@ public IAST setVars(IAST v) {
           "v not matching number of variables: " + v.toString() + ", nvar " + nvar);
     }
     IAST t = vars;
-    vars = v.copyAppendable(); // Arrays.copyOf(v, v.length); // > Java-5
+    vars = v.copy(); // Arrays.copyOf(v, v.length); // > Java-5
     return t;
   }
 
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/polynomials/symbolicexponent/SymbolicPolynomialRing.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/polynomials/symbolicexponent/SymbolicPolynomialRing.java
index fe1788c34..098f693e9 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/polynomials/symbolicexponent/SymbolicPolynomialRing.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/polynomials/symbolicexponent/SymbolicPolynomialRing.java
@@ -378,7 +378,7 @@ public SymbolicPolynomialRing(ExprRingFactory cf, IAST listOfVariables, int n,
     nvar = n;
     tord = t;
     partial = false;
-    vars = listOfVariables.copyAppendable();
+    vars = listOfVariables.copy();
     ZERO = new SymbolicPolynomial(this);
     IExpr coeff = coFac.getONE();
     evzero = new ExpVectorSymbolic(nvar);
@@ -968,7 +968,7 @@ public IAST setVars(IAST v) {
           "v not matching number of variables: " + v.toString() + ", nvar " + nvar);
     }
     IAST t = vars;
-    vars = v.copyAppendable(); // Arrays.copyOf(v, v.length); // > Java-5
+    vars = v.copy(); // Arrays.copyOf(v, v.length); // > Java-5
     return t;
   }
 
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/D.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/D.java
index 31cfc7530..60294dd47 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/D.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/D.java
@@ -286,7 +286,7 @@ private static IAST createDerivativeN(final IExpr header, final IAST args, IExpr
 
   private static IAST addDerivative(final int pos, IAST deriveHead, final IExpr header,
       final IAST args) {
-    IASTMutable derivativeHead1 = deriveHead.copyAppendable();
+    IASTMutable derivativeHead1 = deriveHead.copy();
     for (int i = 1; i < derivativeHead1.size(); i++) {
       if (i == pos) {
         derivativeHead1.set(i, derivativeHead1.get(i).inc());
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/Integrate.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/Integrate.java
index 2a7bdec7a..c932b3b0a 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/Integrate.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/reflection/system/Integrate.java
@@ -88,6 +88,7 @@
 public class Integrate extends AbstractFunctionOptionEvaluator {
 
   private static final Logger LOGGER = LogManager.getLogger();
+
   private static Thread INIT_THREAD = null;
 
   private static final CountDownLatch COUNT_DOWN_LATCH = new CountDownLatch(1);
@@ -350,7 +351,6 @@ public IExpr evaluate(IAST holdallAST, final int argSize, final IExpr[] option,
       }
       boolean showSteps = false;
       if (showSteps) {
-        LOGGER.info(arg1);
         // if (DEBUG_EXPR.contains(arg1)) {
         // System.exit(-1);
         // }
@@ -820,11 +820,6 @@ private static IExpr integrateByRubiRules(IAST arg1, IExpr x, IAST ast, EvalEngi
             IExpr temp = S.Integrate.evalDownRule(EvalEngine.get(), ast);
             if (temp.isPresent()) {
               if (temp.equals(ast)) {
-                if (LOGGER.isDebugEnabled()) {
-                  engine.setQuietMode(false);
-                  Errors.printMessage(S.Integrate, "rubiendless",
-                      F.list(temp, F.stringx("UNKNOWN")), engine);
-                }
                 return F.NIL;
               }
               if (temp.isAST()) {
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/visit/VisitorReplaceArgs.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/visit/VisitorReplaceArgs.java
index fd55b2463..0e2184028 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/visit/VisitorReplaceArgs.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/visit/VisitorReplaceArgs.java
@@ -2,7 +2,6 @@
 
 import org.matheclipse.core.expression.F;
 import org.matheclipse.core.interfaces.IAST;
-import org.matheclipse.core.interfaces.IASTAppendable;
 import org.matheclipse.core.interfaces.IASTMutable;
 import org.matheclipse.core.interfaces.IExpr;
 import org.matheclipse.core.interfaces.ISymbol;
@@ -33,7 +32,7 @@ public IExpr visit(ISymbol element) {
   @Override
   public IExpr visit(IASTMutable ast) {
     IExpr temp;
-    IASTAppendable result = F.NIL;
+    IASTMutable result = F.NIL;
     int size = ast.size();
     boolean evaled = false;
     for (int i = 1; i < size; i++) {
@@ -42,7 +41,7 @@ public IExpr visit(IASTMutable ast) {
       for (int j = 1; i < astSlots.size(); i++) {
         if (astSlots.get(j).equals(temp)) {
           if (result.isNIL()) {
-            result = ast.copyAppendable();
+            result = ast.copy();
           }
           result.set(i, F.Slot(F.ZZ(j)));
           evaled = true;
@@ -55,7 +54,7 @@ public IExpr visit(IASTMutable ast) {
         if (temp.isPresent()) {
           if (result.isNIL()) {
             // something was evaluated - return a new IAST:
-            result = ast.copyAppendable();
+            result = ast.copy();
           }
           result.set(i, temp);
         }
diff --git a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/visit/VisitorReplacePart.java b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/visit/VisitorReplacePart.java
index 26b661dc4..c5c028283 100644
--- a/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/visit/VisitorReplacePart.java
+++ b/symja_android_library/matheclipse-core/src/main/java/org/matheclipse/core/visit/VisitorReplacePart.java
@@ -189,24 +189,23 @@ private IASTAppendable patternIndexRecursive(IPatternMatcher matcher, IAST ast,
     if (matcher.getLHS().isSequence()) {
       IExpr temp = matcher.eval(positionsToMatch, engine);
       if (temp.isPresent()) {
-        if (result.isNIL()) {
+        if (position == 0 && ast.isAssociation()) {
+          result = ((IAssociation) ast).copyAST();
+        } else if (result.isNIL()) {
           result = ast.copyAppendable();
         }
-        if (position == 0 && result.isAssociation()) {
-          result = ((IAssociation) result).copyAST();
-        }
         result.setValue(position, temp);
         return result;
       } else {
         if (ast.get(position).isASTOrAssociation()) {
           temp = visitPatternIndexList((IAST) ast.get(position), positionsToMatch);
           if (temp.isPresent()) {
-            if (result.isNIL()) {
+            if (position == 0 && ast.isAssociation()) {
+              result = ((IAssociation) ast).copyAST();
+            } else if (result.isNIL()) {
               result = ast.copyAppendable();
             }
-            if (position == 0 && result.isAssociation()) {
-              result = ((IAssociation) result).copyAST();
-            }
+
             result.setValue(position, temp);
             return result;
           }