diff --git a/src/org/jetbrains/java/decompiler/main/rels/NestedClassProcessor.java b/src/org/jetbrains/java/decompiler/main/rels/NestedClassProcessor.java
index 649520c..f865167 100644
--- a/src/org/jetbrains/java/decompiler/main/rels/NestedClassProcessor.java
+++ b/src/org/jetbrains/java/decompiler/main/rels/NestedClassProcessor.java
@@ -910,7 +910,7 @@ public class NestedClassProcessor {
     @Override
     public boolean equals(Object o) {
       if (o == this) return true;
-      if (o == null || !(o instanceof VarFieldPair)) return false;
+      if (!(o instanceof VarFieldPair)) return false;
 
       VarFieldPair pair = (VarFieldPair)o;
       return fieldKey.equals(pair.fieldKey) && varPair.equals(pair.varPair);
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/AnnotationExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/AnnotationExprent.java
index b6c828b..13491fc 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/AnnotationExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/AnnotationExprent.java
@@ -4,10 +4,10 @@
 package org.jetbrains.java.decompiler.modules.decompiler.exps;
 
 import org.jetbrains.java.decompiler.main.DecompilerContext;
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 
 import java.util.List;
 
@@ -88,7 +88,7 @@ public class AnnotationExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof AnnotationExprent)) return false;
+    if (!(o instanceof AnnotationExprent)) return false;
 
     AnnotationExprent ann = (AnnotationExprent)o;
     return className.equals(ann.className) &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ArrayExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ArrayExprent.java
index d329ac2..bc482a2 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ArrayExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ArrayExprent.java
@@ -3,12 +3,12 @@
  */
 package org.jetbrains.java.decompiler.modules.decompiler.exps;
 
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor;
 import org.jetbrains.java.decompiler.modules.decompiler.vars.CheckTypesResult;
 import org.jetbrains.java.decompiler.struct.gen.VarType;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -94,7 +94,7 @@ public class ArrayExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof ArrayExprent)) return false;
+    if (!(o instanceof ArrayExprent)) return false;
 
     ArrayExprent arr = (ArrayExprent)o;
     return InterpreterUtil.equalObjects(array, arr.getArray()) &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/AssignmentExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/AssignmentExprent.java
index 2e09e5b..c590ac5 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/AssignmentExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/AssignmentExprent.java
@@ -6,13 +6,13 @@ package org.jetbrains.java.decompiler.modules.decompiler.exps;
 import org.jetbrains.java.decompiler.code.CodeConstants;
 import org.jetbrains.java.decompiler.main.ClassesProcessor.ClassNode;
 import org.jetbrains.java.decompiler.main.DecompilerContext;
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor;
 import org.jetbrains.java.decompiler.modules.decompiler.vars.CheckTypesResult;
 import org.jetbrains.java.decompiler.struct.StructField;
 import org.jetbrains.java.decompiler.struct.gen.VarType;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -162,7 +162,7 @@ public class AssignmentExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof AssignmentExprent)) return false;
+    if (!(o instanceof AssignmentExprent)) return false;
 
     AssignmentExprent as = (AssignmentExprent)o;
     return InterpreterUtil.equalObjects(left, as.getLeft()) &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ConstExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ConstExprent.java
index 1b3d7af..402b9e7 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ConstExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ConstExprent.java
@@ -5,7 +5,6 @@ package org.jetbrains.java.decompiler.modules.decompiler.exps;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
 import org.jetbrains.java.decompiler.main.DecompilerContext;
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.main.extern.IFernflowerPreferences;
 import org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor;
@@ -15,6 +14,7 @@ import org.jetbrains.java.decompiler.struct.match.MatchEngine;
 import org.jetbrains.java.decompiler.struct.match.MatchNode;
 import org.jetbrains.java.decompiler.struct.match.MatchNode.RuleValue;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.util.TextUtil;
 
 import java.util.*;
@@ -285,7 +285,7 @@ public class ConstExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof ConstExprent)) return false;
+    if (!(o instanceof ConstExprent)) return false;
 
     ConstExprent cn = (ConstExprent)o;
     return InterpreterUtil.equalObjects(constType, cn.getConstType()) &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ExitExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ExitExprent.java
index 67cf69b..25506fa 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ExitExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/ExitExprent.java
@@ -6,7 +6,6 @@ package org.jetbrains.java.decompiler.modules.decompiler.exps;
 import org.jetbrains.java.decompiler.code.CodeConstants;
 import org.jetbrains.java.decompiler.main.ClassesProcessor.ClassNode;
 import org.jetbrains.java.decompiler.main.DecompilerContext;
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.main.rels.MethodWrapper;
 import org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor;
@@ -16,6 +15,7 @@ import org.jetbrains.java.decompiler.struct.gen.VarType;
 import org.jetbrains.java.decompiler.struct.match.MatchEngine;
 import org.jetbrains.java.decompiler.struct.match.MatchNode;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -123,7 +123,7 @@ public class ExitExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof ExitExprent)) return false;
+    if (!(o instanceof ExitExprent)) return false;
 
     ExitExprent et = (ExitExprent)o;
     return exitType == et.getExitType() &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/FieldExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/FieldExprent.java
index 02425fc..264347e 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/FieldExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/FieldExprent.java
@@ -6,7 +6,6 @@ package org.jetbrains.java.decompiler.modules.decompiler.exps;
 import org.jetbrains.java.decompiler.code.CodeConstants;
 import org.jetbrains.java.decompiler.main.ClassesProcessor.ClassNode;
 import org.jetbrains.java.decompiler.main.DecompilerContext;
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.main.rels.MethodWrapper;
 import org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor;
@@ -19,6 +18,7 @@ import org.jetbrains.java.decompiler.struct.match.MatchEngine;
 import org.jetbrains.java.decompiler.struct.match.MatchNode;
 import org.jetbrains.java.decompiler.struct.match.MatchNode.RuleValue;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.util.TextUtil;
 
 import java.util.ArrayList;
@@ -155,7 +155,7 @@ public class FieldExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof FieldExprent)) return false;
+    if (!(o instanceof FieldExprent)) return false;
 
     FieldExprent ft = (FieldExprent)o;
     return InterpreterUtil.equalObjects(name, ft.getName()) &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/FunctionExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/FunctionExprent.java
index 487d939..2c5a2ac 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/FunctionExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/FunctionExprent.java
@@ -4,7 +4,6 @@
 package org.jetbrains.java.decompiler.modules.decompiler.exps;
 
 import org.jetbrains.java.decompiler.code.CodeConstants;
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.modules.decompiler.ExprProcessor;
 import org.jetbrains.java.decompiler.modules.decompiler.vars.CheckTypesResult;
@@ -13,6 +12,7 @@ import org.jetbrains.java.decompiler.struct.match.MatchEngine;
 import org.jetbrains.java.decompiler.struct.match.MatchNode;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
 import org.jetbrains.java.decompiler.util.ListStack;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 
 import java.util.*;
 
@@ -413,7 +413,7 @@ public class FunctionExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof FunctionExprent)) return false;
+    if (!(o instanceof FunctionExprent)) return false;
 
     FunctionExprent fe = (FunctionExprent)o;
     return funcType == fe.getFuncType() &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/IfExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/IfExprent.java
index 6f10a69..32dd0ba 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/IfExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/IfExprent.java
@@ -3,13 +3,15 @@
  */
 package org.jetbrains.java.decompiler.modules.decompiler.exps;
 
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.struct.gen.VarType;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
 import org.jetbrains.java.decompiler.util.ListStack;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
 
 public class IfExprent extends Exprent {
 
@@ -115,7 +117,7 @@ public class IfExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof IfExprent)) return false;
+    if (!(o instanceof IfExprent)) return false;
 
     IfExprent ie = (IfExprent)o;
     return InterpreterUtil.equalObjects(condition, ie.getCondition());
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/InvocationExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/InvocationExprent.java
index 5175743..12d4600 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/InvocationExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/InvocationExprent.java
@@ -6,7 +6,6 @@ package org.jetbrains.java.decompiler.modules.decompiler.exps;
 import org.jetbrains.java.decompiler.code.CodeConstants;
 import org.jetbrains.java.decompiler.main.ClassesProcessor.ClassNode;
 import org.jetbrains.java.decompiler.main.DecompilerContext;
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.main.extern.IFernflowerPreferences;
 import org.jetbrains.java.decompiler.main.rels.MethodWrapper;
@@ -26,6 +25,7 @@ import org.jetbrains.java.decompiler.struct.match.MatchNode;
 import org.jetbrains.java.decompiler.struct.match.MatchNode.RuleValue;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
 import org.jetbrains.java.decompiler.util.ListStack;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.util.TextUtil;
 
 import java.lang.reflect.Method;
@@ -539,7 +539,7 @@ public class InvocationExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof InvocationExprent)) return false;
+    if (!(o instanceof InvocationExprent)) return false;
 
     InvocationExprent it = (InvocationExprent)o;
     return InterpreterUtil.equalObjects(name, it.getName()) &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/MonitorExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/MonitorExprent.java
index 795ac06..4172874 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/MonitorExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/MonitorExprent.java
@@ -3,9 +3,9 @@
  */
 package org.jetbrains.java.decompiler.modules.decompiler.exps;
 
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -61,7 +61,7 @@ public class MonitorExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof MonitorExprent)) return false;
+    if (!(o instanceof MonitorExprent)) return false;
 
     MonitorExprent me = (MonitorExprent)o;
     return monType == me.getMonType() &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/NewExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/NewExprent.java
index 96d31fa..84ac1ac 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/NewExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/NewExprent.java
@@ -7,7 +7,6 @@ import org.jetbrains.java.decompiler.code.CodeConstants;
 import org.jetbrains.java.decompiler.main.ClassWriter;
 import org.jetbrains.java.decompiler.main.ClassesProcessor.ClassNode;
 import org.jetbrains.java.decompiler.main.DecompilerContext;
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.main.extern.IFernflowerLogger;
 import org.jetbrains.java.decompiler.main.extern.IFernflowerPreferences;
@@ -20,6 +19,7 @@ import org.jetbrains.java.decompiler.struct.gen.generics.GenericClassDescriptor;
 import org.jetbrains.java.decompiler.struct.gen.generics.GenericMain;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
 import org.jetbrains.java.decompiler.util.ListStack;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -423,7 +423,7 @@ public class NewExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof NewExprent)) return false;
+    if (!(o instanceof NewExprent)) return false;
 
     NewExprent ne = (NewExprent)o;
     return InterpreterUtil.equalObjects(newType, ne.getNewType()) &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/SwitchExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/SwitchExprent.java
index 1b1025e..3a97175 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/SwitchExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/SwitchExprent.java
@@ -3,11 +3,11 @@
  */
 package org.jetbrains.java.decompiler.modules.decompiler.exps;
 
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.modules.decompiler.vars.CheckTypesResult;
 import org.jetbrains.java.decompiler.struct.gen.VarType;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -92,7 +92,7 @@ public class SwitchExprent extends Exprent {
       return true;
     }
 
-    if (o == null || !(o instanceof SwitchExprent)) {
+    if (!(o instanceof SwitchExprent)) {
       return false;
     }
 
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/VarExprent.java b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/VarExprent.java
index 710bd1b..8c2a553 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/exps/VarExprent.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/exps/VarExprent.java
@@ -7,7 +7,6 @@ import org.jetbrains.java.decompiler.code.CodeConstants;
 import org.jetbrains.java.decompiler.main.ClassWriter;
 import org.jetbrains.java.decompiler.main.ClassesProcessor.ClassNode;
 import org.jetbrains.java.decompiler.main.DecompilerContext;
-import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.main.collectors.BytecodeMappingTracer;
 import org.jetbrains.java.decompiler.main.extern.IFernflowerPreferences;
 import org.jetbrains.java.decompiler.main.rels.MethodWrapper;
@@ -26,6 +25,7 @@ import org.jetbrains.java.decompiler.struct.match.MatchEngine;
 import org.jetbrains.java.decompiler.struct.match.MatchNode;
 import org.jetbrains.java.decompiler.struct.match.MatchNode.RuleValue;
 import org.jetbrains.java.decompiler.util.InterpreterUtil;
+import org.jetbrains.java.decompiler.util.TextBuffer;
 import org.jetbrains.java.decompiler.util.TextUtil;
 
 import java.util.ArrayList;
@@ -176,7 +176,7 @@ public class VarExprent extends Exprent {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof VarExprent)) return false;
+    if (!(o instanceof VarExprent)) return false;
 
     VarExprent ve = (VarExprent)o;
     return index == ve.getIndex() &&
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/sforms/FlattenStatementsHelper.java b/src/org/jetbrains/java/decompiler/modules/decompiler/sforms/FlattenStatementsHelper.java
index f1dbf9f..b465126 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/sforms/FlattenStatementsHelper.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/sforms/FlattenStatementsHelper.java
@@ -486,7 +486,7 @@ public class FlattenStatementsHelper {
     @Override
     public boolean equals(Object o) {
       if (o == this) return true;
-      if (o == null || !(o instanceof FinallyPathWrapper)) return false;
+      if (!(o instanceof FinallyPathWrapper)) return false;
 
       FinallyPathWrapper fpw = (FinallyPathWrapper)o;
       return (source + ":" + destination + ":" + entry).equals(fpw.source + ":" + fpw.destination + ":" + fpw.entry);
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionEdge.java b/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionEdge.java
index 347a6b6..2e67a88 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionEdge.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionEdge.java
@@ -24,7 +24,7 @@ public class VarVersionEdge { // FIXME: can be removed?
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof VarVersionEdge)) return false;
+    if (!(o instanceof VarVersionEdge)) return false;
 
     VarVersionEdge edge = (VarVersionEdge)o;
     return type == edge.type && source == edge.source && dest == edge.dest;
diff --git a/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionPair.java b/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionPair.java
index 59e29c2..8554988 100644
--- a/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionPair.java
+++ b/src/org/jetbrains/java/decompiler/modules/decompiler/vars/VarVersionPair.java
@@ -28,7 +28,7 @@ public class VarVersionPair {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof VarVersionPair)) return false;
+    if (!(o instanceof VarVersionPair)) return false;
 
     VarVersionPair paar = (VarVersionPair)o;
     return var == paar.var && version == paar.version;
diff --git a/src/org/jetbrains/java/decompiler/struct/consts/LinkConstant.java b/src/org/jetbrains/java/decompiler/struct/consts/LinkConstant.java
index 4a24686..d8a92ca 100644
--- a/src/org/jetbrains/java/decompiler/struct/consts/LinkConstant.java
+++ b/src/org/jetbrains/java/decompiler/struct/consts/LinkConstant.java
@@ -63,7 +63,7 @@ public class LinkConstant extends PooledConstant {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof LinkConstant)) return false;
+    if (!(o instanceof LinkConstant)) return false;
 
     LinkConstant cn = (LinkConstant)o;
     return this.type == cn.type &&
diff --git a/src/org/jetbrains/java/decompiler/struct/consts/PrimitiveConstant.java b/src/org/jetbrains/java/decompiler/struct/consts/PrimitiveConstant.java
index 3d8bfb0..626a91b 100644
--- a/src/org/jetbrains/java/decompiler/struct/consts/PrimitiveConstant.java
+++ b/src/org/jetbrains/java/decompiler/struct/consts/PrimitiveConstant.java
@@ -40,7 +40,7 @@ public class PrimitiveConstant extends PooledConstant {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof PrimitiveConstant)) return false;
+    if (!(o instanceof PrimitiveConstant)) return false;
 
     PrimitiveConstant cn = (PrimitiveConstant)o;
     return this.type == cn.type &&
diff --git a/src/org/jetbrains/java/decompiler/struct/gen/FieldDescriptor.java b/src/org/jetbrains/java/decompiler/struct/gen/FieldDescriptor.java
index 765820c..94add14 100644
--- a/src/org/jetbrains/java/decompiler/struct/gen/FieldDescriptor.java
+++ b/src/org/jetbrains/java/decompiler/struct/gen/FieldDescriptor.java
@@ -36,7 +36,7 @@ public class FieldDescriptor {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof FieldDescriptor)) return false;
+    if (!(o instanceof FieldDescriptor)) return false;
 
     FieldDescriptor fd = (FieldDescriptor)o;
     return type.equals(fd.type);
diff --git a/src/org/jetbrains/java/decompiler/struct/gen/MethodDescriptor.java b/src/org/jetbrains/java/decompiler/struct/gen/MethodDescriptor.java
index 89c0cc8..102393c 100644
--- a/src/org/jetbrains/java/decompiler/struct/gen/MethodDescriptor.java
+++ b/src/org/jetbrains/java/decompiler/struct/gen/MethodDescriptor.java
@@ -114,7 +114,7 @@ public class MethodDescriptor {
   @Override
   public boolean equals(Object o) {
     if (o == this) return true;
-    if (o == null || !(o instanceof MethodDescriptor)) return false;
+    if (!(o instanceof MethodDescriptor)) return false;
 
     MethodDescriptor md = (MethodDescriptor)o;
     return ret.equals(md.ret) && Arrays.equals(params, md.params);
diff --git a/src/org/jetbrains/java/decompiler/struct/gen/VarType.java b/src/org/jetbrains/java/decompiler/struct/gen/VarType.java
index 5bb88b5..384d31b 100644
--- a/src/org/jetbrains/java/decompiler/struct/gen/VarType.java
+++ b/src/org/jetbrains/java/decompiler/struct/gen/VarType.java
@@ -265,7 +265,7 @@ public class VarType {  // TODO: optimize switch
       return true;
     }
 
-    if (o == null || !(o instanceof VarType)) {
+    if (!(o instanceof VarType)) {
       return false;
     }
 
diff --git a/src/org/jetbrains/java/decompiler/util/FastFixedSetFactory.java b/src/org/jetbrains/java/decompiler/util/FastFixedSetFactory.java
index c852838..80ac7d6 100644
--- a/src/org/jetbrains/java/decompiler/util/FastFixedSetFactory.java
+++ b/src/org/jetbrains/java/decompiler/util/FastFixedSetFactory.java
@@ -1,7 +1,10 @@
 // Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package org.jetbrains.java.decompiler.util;
 
-import java.util.*;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Set;
 
 public class FastFixedSetFactory<E> {
 
@@ -145,7 +148,7 @@ public class FastFixedSetFactory<E> {
 
     public boolean equals(Object o) {
       if (o == this) return true;
-      if (o == null || !(o instanceof FastFixedSet)) return false;
+      if (!(o instanceof FastFixedSet)) return false;
 
       int[] extdata = ((FastFixedSet)o).getData();
       int[] intdata = data;
diff --git a/src/org/jetbrains/java/decompiler/util/FastSparseSetFactory.java b/src/org/jetbrains/java/decompiler/util/FastSparseSetFactory.java
index f94360d..91cdabc 100644
--- a/src/org/jetbrains/java/decompiler/util/FastSparseSetFactory.java
+++ b/src/org/jetbrains/java/decompiler/util/FastSparseSetFactory.java
@@ -263,7 +263,7 @@ public class FastSparseSetFactory<E> {
 
     public boolean equals(Object o) {
       if (o == this) return true;
-      if (o == null || !(o instanceof FastSparseSet)) return false;
+      if (!(o instanceof FastSparseSet)) return false;
 
       int[] longdata = ((FastSparseSet)o).getData();
       int[] shortdata = data;