Fixes several Sonar violations

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/ConfusingConditionCheck.java

@@ -320,13 +320,10 @@ private static int getCountOfToken(DetailAST detAst, int type) {
 			while (detAst != null) {
 				count += detAst.getChildCount(type);
 				final DetailAST detAstChild = detAst.getFirstChild();
-				if (detAstChild == null) {
-					detAst = detAst.getNextSibling();
-				} else {
+				if (detAstChild != null) {
 					count += getCountOfToken(detAstChild, type);
-					detAst = detAst.getNextSibling();
 				}
-
+				detAst = detAst.getNextSibling();
 			}
 		}
 		return count;

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/CustomDeclarationOrderCheck.java

@@ -264,7 +264,7 @@ public void setCustomDeclarationOrder(final String inputOrderDeclaration)
             }
             catch (StringIndexOutOfBoundsException exp) {
                 //if the structure of the input rule isn't correct
-                throw new RuntimeException("Unable to parse input rule: "
+                throw new IllegalArgumentException("Unable to parse input rule: "
                         + currentState, exp);
             }
         }
@@ -806,7 +806,7 @@ private static boolean isAnonymousClass(DetailAST expressionAst)
      */
     private static String getCombinedModifiersList(final DetailAST ast)
     {
-        final StringBuffer modifiers = new StringBuffer();
+        final StringBuilder modifiers = new StringBuilder();
         DetailAST astNode = ast.findFirstToken(TokenTypes.MODIFIERS);
         if (astNode.getFirstChild() == null) {
             //if we met package level modifier

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/IllegalCatchExtendedCheck.java

@@ -105,14 +105,12 @@ public void visitToken(DetailAST detailAST)
         // For warnings disable first lvl child must be an EXPR and
         // second lvl child must be IDENT or LITERAL_NEW with
         // appropriate boolean flags.
-        final boolean noWarning = (throwAST != null
+        final boolean noWarning = throwAST != null
                 && firstLvlChild != null
                 && secondLvlChild != null
              && firstLvlChild.getType() == TokenTypes.EXPR
-             && ((allowThrow && secondLvlChild.getType()
-                     == TokenTypes.IDENT)
-             || (allowRethrow && secondLvlChild.getType()
-                     == TokenTypes.LITERAL_NEW)));
+             && ((allowThrow && secondLvlChild.getType() == TokenTypes.IDENT)
+             || (allowRethrow && secondLvlChild.getType() == TokenTypes.LITERAL_NEW));
 
         final DetailAST excType = paramDef.findFirstToken(TokenTypes.TYPE);
         final FullIdent ident = CheckUtils.createFullType(excType);
@@ -137,7 +135,7 @@ public DetailAST getThrowAST(DetailAST parentAST)
             if (currentNode.getType() != TokenTypes.PARAMETER_DEF
                     && currentNode.getNumberOfChildren() > 0)
             {
-                final DetailAST astResult = (getThrowAST(currentNode));
+                final DetailAST astResult = getThrowAST(currentNode);
                 if (astResult != null) {
                     return astResult;
                 }

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/MultipleVariableDeclarationsExtendedCheck.java

@@ -106,8 +106,8 @@ public void work(DetailAST ast)
 	{
 
 		DetailAST nextNode = ast.getNextSibling();
-		final boolean isCommaSeparated = ((nextNode != null) && (nextNode
-				.getType() == TokenTypes.COMMA));
+		final boolean isCommaSeparated = (nextNode != null) && (nextNode
+				.getType() == TokenTypes.COMMA);
 
 		if (nextNode == null) {
 			// no nextMethods statement - no check
@@ -144,10 +144,8 @@ public void visitToken(DetailAST ast)
 	{
 
 		final DetailAST token = ast;
-		final boolean inFor = (ast.getParent().getType()
-				== TokenTypes.FOR_INIT);
-		final boolean inClass = (ast.getParent().getParent().getType()
-				== TokenTypes.CLASS_DEF);
+		final boolean inFor = ast.getParent().getType() == TokenTypes.FOR_INIT;
+		final boolean inClass = ast.getParent().getParent().getType() == TokenTypes.CLASS_DEF;
 
 		if (inClass) {
 			work(token);

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/NoNullForCollectionReturnCheck.java

@@ -140,15 +140,13 @@ public void visitToken(DetailAST detailAST)
         switch (detailAST.getType())
         {
             case TokenTypes.METHOD_DEF:
-            {
                 if (isReturnCollection(detailAST))
                 {
                     methodDefs.push(detailAST);
                 }
                 break;
-            }
+
             case TokenTypes.LITERAL_RETURN:
-            {
                 if (!methodDefs.isEmpty())
                 {
                     DetailAST currentMethodDef = getMethodDef(detailAST);
@@ -161,7 +159,7 @@ && isReturnedValueBeNull(detailAST))))
                     }
                 }
                 break;
-            }
+
             default:
                 Utils.reportInvalidToken(detailAST.getType());
                 break;

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/OverridableMethodInConstructorCheck.java

@@ -144,26 +144,26 @@ public class OverridableMethodInConstructorCheck extends Check
      * A key is using to build a warning message about calls of an overridable
      * methods from any constructor body.
      * */
-    private final String keyCtor = "constructor";
+    private static final String KEY_CTOR = "constructor";
 
     /**
      * A key is using to build a warning message about calls of an overridable
      * methods from any clone() method is implemented from Cloneable interface.
      * */
-    private final String keyClone = "'clone()' method";
+    private static final String KEY_CLONE = "'clone()' method";
 
     /**
      * A key is using to build a warning message about calls of an overridable
      * methods from any readObject() method is implemented from Serializable
      * interface.
      * */
-    private final String keyReadObject = "'readObject()' method";
+    private static final String KEY_READ_OBJECT = "'readObject()' method";
 
     /**
      * A list contains all METHOD_CALL DetailAST nodes that have been already
      * visited by check.
      * */
-    private List<DetailAST> visitedMethodCalls = new LinkedList<DetailAST>();
+    private final List<DetailAST> visitedMethodCalls = new LinkedList<DetailAST>();
 
     /**
      * A current MethodDef AST is being processed by check.
@@ -268,7 +268,7 @@ public void visitToken(final DetailAST detailAST)
             switch (detailAST.getType()) {
 
                 case TokenTypes.CTOR_DEF:
-                    logWarnings(detailAST, keyCtor);
+                logWarnings(detailAST, KEY_CTOR);
                     break;
 
                 case TokenTypes.METHOD_DEF:
@@ -279,13 +279,13 @@ public void visitToken(final DetailAST detailAST)
                     if (checkCloneMethod && "clone".equals(methodName)
                         && realizesAnInterface(classDef, Cloneable.class.getSimpleName()))
                     {
-                        logWarnings(detailAST, keyClone);
+                    logWarnings(detailAST, KEY_CLONE);
                     }
                     else if (checkReadObjectMethod
                         && "readObject".equals(methodName)
                         && realizesAnInterface(classDef, Serializable.class.getSimpleName()))
                     {
-                        logWarnings(detailAST, keyReadObject);
+                    logWarnings(detailAST, KEY_READ_OBJECT);
                     }
                     break;
 

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/RedundantReturnCheck.java

@@ -230,7 +230,8 @@ private static List<DetailAST> getRedundantReturnsInTryCatchBlock(DetailAST tryA
 
 		// look for redundant returns in all catches
 		for (DetailAST catchBlockAst = getNextCatchBlock(blockAst);
-				catchBlockAst != null;) {
+				catchBlockAst != null;
+		                catchBlockAst = getNextCatchBlock(blockAst)) {
 			DetailAST lastStatementOfCatchBlockAst = catchBlockAst
 				.getLastChild().getLastChild().getPreviousSibling();
 
@@ -243,7 +244,6 @@ private static List<DetailAST> getRedundantReturnsInTryCatchBlock(DetailAST tryA
 				}
 			}
 			blockAst = blockAst.getNextSibling();
-			catchBlockAst = getNextCatchBlock(blockAst);
 		}
 
 		// if redundant return is in finally block

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/ReturnCountExtendedCheck.java

@@ -433,7 +433,7 @@ private static List<DetailAST> getChildren(final DetailAST node)
      */
     private static boolean matches(String string, Collection<String> patterns) {
         boolean result = false;
-        if (string != null && patterns != null && patterns.size() > 0) {
+        if (string != null && patterns != null && !patterns.isEmpty()) {
             for (String pattern : patterns) {
                 if (string.matches(pattern)) {
                     result = true;

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/coding/TernaryPerExpressionCountCheck.java

@@ -247,8 +247,7 @@ private static DetailAST getNextNode(DetailAST expressionNode,
                 currentNode = currentNode.getParent();
             }
         }
-        currentNode = toVisit;
 
-        return currentNode;
+        return toVisit;
     }
 }

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/design/ChildBlockLengthCheck.java

@@ -152,7 +152,7 @@ public void visitToken(DetailAST ast)
                 final List<DetailAST> badChildBlocks = getBadChildBlocks(
                         childBlocks, parentBlockSize);
 
-                if (badChildBlocks.size() == 0) {
+                if (badChildBlocks.isEmpty()) {
                     for (DetailAST childBlock : childBlocks) {
                         visitToken(childBlock);
                     }

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/design/HideUtilityClassConstructorCheck.java

@@ -99,7 +99,7 @@ public void visitToken(DetailAST ast)
             child = child.getNextSibling();
         }
 
-        final boolean hasAccessibleCtor = (hasDefaultCtor || hasPublicCtor);
+        final boolean hasAccessibleCtor = hasDefaultCtor || hasPublicCtor;
 
         // figure out if class extends java.lang.object directly
         // keep it simple for now and get a 99% solution

sevntu-checks/src/main/java/com/github/sevntu/checkstyle/checks/naming/EnumValueNameCheck.java

@@ -218,15 +218,15 @@ private boolean isClassEnumeration(DetailAST ast)
             hasMembers(DetailAST ast, List<Pattern> excludes)
     {
         final DetailAST objBlock = ast.getParent();
-        assert (objBlock.getType() == TokenTypes.OBJBLOCK);
+        assert objBlock.getType() == TokenTypes.OBJBLOCK;
         boolean memberFound = false;
         for (DetailAST member = objBlock.getFirstChild(); member != null; member = member
                 .getNextSibling()) {
             if (member.getType() == TokenTypes.METHOD_DEF
                     || member.getType() == TokenTypes.VARIABLE_DEF) {
                 final DetailAST memberIdent = member
                         .findFirstToken(TokenTypes.IDENT);
-                assert (memberIdent != null);
+                assert memberIdent != null;
                 final String identifierStr = memberIdent.getText();
                 if (!isAnyMatched(excludes, identifierStr)) {
                     memberFound = true;