diff --git a/java/debugger/impl/src/com/intellij/debugger/impl/DebuggerUtilsEx.java b/java/debugger/impl/src/com/intellij/debugger/impl/DebuggerUtilsEx.java
index 6d34c7f0dc69..2e8f075d584d 100644
--- a/java/debugger/impl/src/com/intellij/debugger/impl/DebuggerUtilsEx.java
+++ b/java/debugger/impl/src/com/intellij/debugger/impl/DebuggerUtilsEx.java
@@ -254,13 +254,7 @@ public abstract class DebuggerUtilsEx extends DebuggerUtils {
   }
   
   public static int getEnabledNumber(ClassFilter[] classFilters) {
-    int res = 0;
-    for (ClassFilter filter : classFilters) {
-      if (filter.isEnabled()) {
-        res++;
-      }
-    }
-    return res;
+    return (int)Arrays.stream(classFilters).filter(ClassFilter::isEnabled).count();
   }
 
   public static ClassFilter[] readFilters(List<Element> children) throws InvalidDataException {
diff --git a/java/java-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationPresentation.java b/java/java-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationPresentation.java
index 3988ee7e4a59..2853f90278a8 100644
--- a/java/java-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationPresentation.java
+++ b/java/java-impl/src/com/intellij/codeInspection/deadCode/UnusedDeclarationPresentation.java
@@ -204,13 +204,8 @@ public class UnusedDeclarationPresentation extends DefaultInspectionToolPresenta
     if (showFixes) {
       final TreePath[] paths = tree.getSelectionPaths();
       if (paths != null) {
-        int count = 0;
-        for (TreePath path : paths) {
-          final Object component = path.getLastPathComponent();
-          if (component instanceof ProblemDescriptionNode) {
-            count++;
-          }
-        }
+        long count = Arrays.stream(paths).map(TreePath::getLastPathComponent)
+          .filter(component -> component instanceof ProblemDescriptionNode).count();
         if (count > 0) {
           final QuickFixAction[] fixes = super.getQuickFixes(refElements, tree);
           if (fixes != null) {
diff --git a/platform/lang-impl/src/com/intellij/find/actions/ShowUsagesAction.java b/platform/lang-impl/src/com/intellij/find/actions/ShowUsagesAction.java
index 7f3f2ea0c5e0..5e631483f15d 100644
--- a/platform/lang-impl/src/com/intellij/find/actions/ShowUsagesAction.java
+++ b/platform/lang-impl/src/com/intellij/find/actions/ShowUsagesAction.java
@@ -813,11 +813,7 @@ public class ShowUsagesAction extends AnAction implements PopupAction {
   }
 
   private static int filtered(@NotNull List<Usage> usages, @NotNull UsageViewImpl usageView) {
-    int count=0;
-    for (Usage usage : usages) {
-      if (!usageView.isVisible(usage)) count++;
-    }
-    return count;
+    return (int)usages.stream().filter(usage -> !usageView.isVisible(usage)).count();
   }
 
   private static int getUsageOffset(@NotNull Usage usage) {
diff --git a/platform/lang-impl/src/com/intellij/refactoring/memberPushDown/AbstractPushDownDialog.java b/platform/lang-impl/src/com/intellij/refactoring/memberPushDown/AbstractPushDownDialog.java
index b4c58fc8ee27..b093a253abbf 100644
--- a/platform/lang-impl/src/com/intellij/refactoring/memberPushDown/AbstractPushDownDialog.java
+++ b/platform/lang-impl/src/com/intellij/refactoring/memberPushDown/AbstractPushDownDialog.java
@@ -32,6 +32,7 @@ import java.awt.*;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.stream.Collectors;
 
 public abstract class AbstractPushDownDialog<MemberInfo extends MemberInfoBase<Member>,
                                              Member extends PsiElement,
@@ -60,13 +61,9 @@ public abstract class AbstractPushDownDialog<MemberInfo extends MemberInfoBase<M
   }
 
   public ArrayList<MemberInfo> getSelectedMemberInfos() {
-    ArrayList<MemberInfo> list = new ArrayList<>(myMemberInfos.size());
-    for (MemberInfo info : myMemberInfos) {
-      if (info.isChecked() && myMemberInfoModel.isMemberEnabled(info)) {
-        list.add(info);
-      }
-    }
-    return list;
+    return myMemberInfos.stream()
+      .filter(info -> info.isChecked() && myMemberInfoModel.isMemberEnabled(info))
+      .collect(Collectors.toCollection(ArrayList::new));
   }
 
   protected String getDimensionServiceKey() {
diff --git a/platform/lang-impl/src/com/intellij/usageView/impl/UsageViewManagerImpl.java b/platform/lang-impl/src/com/intellij/usageView/impl/UsageViewManagerImpl.java
index 3366e282840f..8824592ce7f5 100644
--- a/platform/lang-impl/src/com/intellij/usageView/impl/UsageViewManagerImpl.java
+++ b/platform/lang-impl/src/com/intellij/usageView/impl/UsageViewManagerImpl.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2009 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -30,6 +30,7 @@ import com.intellij.usages.UsageView;
 import org.jetbrains.annotations.NotNull;
 
 import javax.swing.*;
+import java.util.Arrays;
 
 public class UsageViewManagerImpl extends UsageViewManager {
   private final Key<Boolean> REUSABLE_CONTENT_KEY = Key.create("UsageTreeManager.REUSABLE_CONTENT_KEY");
@@ -99,14 +100,8 @@ public class UsageViewManagerImpl extends UsageViewManager {
 
   private int getContentCount(boolean reusable) {
     Key<Boolean> contentKey = reusable ? REUSABLE_CONTENT_KEY : NOT_REUSABLE_CONTENT_KEY;
-    int count = 0;
     Content[] contents = myFindContentManager.getContents();
-    for (Content content : contents) {
-      if (content.getUserData(contentKey) != null) {
-        count++;
-      }
-    }
-    return count;
+    return (int)Arrays.stream(contents).filter(content -> content.getUserData(contentKey) != null).count();
   }
 
   @Override
diff --git a/platform/platform-api/src/com/intellij/ui/tabs/impl/singleRow/SingleRowLayout.java b/platform/platform-api/src/com/intellij/ui/tabs/impl/singleRow/SingleRowLayout.java
index f57e6dc7ce59..d666ec324c81 100644
--- a/platform/platform-api/src/com/intellij/ui/tabs/impl/singleRow/SingleRowLayout.java
+++ b/platform/platform-api/src/com/intellij/ui/tabs/impl/singleRow/SingleRowLayout.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -209,10 +209,7 @@ public class SingleRowLayout extends TabLayout {
   }
 
   protected void updateMoreIconVisibility(SingleRowPassInfo data) {
-    int counter = 0;
-    for (TabInfo tabInfo : data.myVisibleInfos) {
-      if (isTabHidden(tabInfo)) counter++;
-    }
+    int counter = (int)data.myVisibleInfos.stream().filter(this::isTabHidden).count();
     myMoreIcon.updateCounter(counter);
   }
 
diff --git a/plugins/copyright/src/com/maddyhome/idea/copyright/actions/AbstractFileProcessor.java b/plugins/copyright/src/com/maddyhome/idea/copyright/actions/AbstractFileProcessor.java
index 7b020a0e6597..0cadeaf43a09 100644
--- a/plugins/copyright/src/com/maddyhome/idea/copyright/actions/AbstractFileProcessor.java
+++ b/plugins/copyright/src/com/maddyhome/idea/copyright/actions/AbstractFileProcessor.java
@@ -31,7 +31,6 @@ import com.intellij.openapi.roots.ContentIterator;
 import com.intellij.openapi.roots.ModuleFileIndex;
 import com.intellij.openapi.roots.ModuleRootManager;
 import com.intellij.openapi.vfs.ReadonlyStatusHandler;
-import com.intellij.openapi.vfs.VfsUtilCore;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiDirectory;
 import com.intellij.psi.PsiFile;
@@ -243,12 +242,8 @@ public abstract class AbstractFileProcessor {
   }
 
   private void handleFiles(final List<PsiFile> files) {
-    final List<VirtualFile> vFiles = new ArrayList<>();
-    for (PsiFile psiFile : files) {
-      vFiles.add(psiFile.getVirtualFile());
-    }
-    if (!ReadonlyStatusHandler.getInstance(myProject).ensureFilesWritable(VfsUtilCore.toVirtualFileArray(vFiles))
-      .hasReadonlyFiles()) {
+    final VirtualFile[] vFiles = files.stream().map(PsiFile::getVirtualFile).toArray(VirtualFile[]::new);
+    if (!ReadonlyStatusHandler.getInstance(myProject).ensureFilesWritable(vFiles).hasReadonlyFiles()) {
       if (!files.isEmpty()) {
         final Runnable[] resultRunnable = new Runnable[1];
         execute(() -> resultRunnable[0] = prepareFiles(files), () -> {
diff --git a/plugins/devkit/src/build/PrepareAllToDeployAction.java b/plugins/devkit/src/build/PrepareAllToDeployAction.java
index 2075931b31b0..a8e454678435 100644
--- a/plugins/devkit/src/build/PrepareAllToDeployAction.java
+++ b/plugins/devkit/src/build/PrepareAllToDeployAction.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -26,6 +26,7 @@ import org.jetbrains.idea.devkit.DevKitBundle;
 import org.jetbrains.idea.devkit.module.PluginModuleType;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 public class PrepareAllToDeployAction extends PrepareToDeployAction {
@@ -51,14 +52,11 @@ public class PrepareAllToDeployAction extends PrepareToDeployAction {
   }
 
   public void update(AnActionEvent e) {
-    int moduleCount = 0;
+    long moduleCount = 0;
     final Project project = e.getData(CommonDataKeys.PROJECT);
     if (project != null) {
-      for (Module aModule : (ModuleManager.getInstance(project).getModules())) {
-        if (PluginModuleType.isOfType(aModule)) {
-          moduleCount++;
-        }
-      }
+      moduleCount = Arrays.stream(ModuleManager.getInstance(project).getModules()).filter(PluginModuleType::isOfType)
+        .limit(2).count();
     }
     boolean enabled = false;
     if (moduleCount > 1) {
diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/mvc/projectView/AbstractFolderNode.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/mvc/projectView/AbstractFolderNode.java
index 0b6cdd2aa2a7..7a5f0bda5e03 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/mvc/projectView/AbstractFolderNode.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/mvc/projectView/AbstractFolderNode.java
@@ -36,10 +36,11 @@ import org.jetbrains.plugins.groovy.lang.psi.GroovyFile;
 import org.jetbrains.plugins.groovy.lang.psi.api.statements.typedef.GrTypeDefinition;
 
 import javax.swing.*;
-import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.stream.Collectors;
 
 /**
  * @author Dmitry Krasilschikov
@@ -76,12 +77,9 @@ public class AbstractFolderNode extends AbstractMvcPsiNodeDescriptor {
       return Collections.emptyList();
     }
 
-    final List<AbstractTreeNode> children = new ArrayList<>();
-
     // scan folder's children
-    for (PsiDirectory subDir : directory.getSubdirectories()) {
-      children.add(createFolderNode(subDir));
-    }
+    final List<AbstractTreeNode> children = Arrays.stream(directory.getSubdirectories())
+      .map(this::createFolderNode).collect(Collectors.toList());
 
     for (PsiFile file : directory.getFiles()) {
       processNotDirectoryFile(children, file);
diff --git a/plugins/svn4idea/src/org/jetbrains/idea/svn/update/AbstractSvnUpdateIntegrateEnvironment.java b/plugins/svn4idea/src/org/jetbrains/idea/svn/update/AbstractSvnUpdateIntegrateEnvironment.java
index 107e5c96b140..657cb4c8dae5 100644
--- a/plugins/svn4idea/src/org/jetbrains/idea/svn/update/AbstractSvnUpdateIntegrateEnvironment.java
+++ b/plugins/svn4idea/src/org/jetbrains/idea/svn/update/AbstractSvnUpdateIntegrateEnvironment.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2012 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -41,6 +41,7 @@ import org.jetbrains.idea.svn.actions.SvnMergeProvider;
 
 import java.io.File;
 import java.util.*;
+import java.util.stream.Collectors;
 
 public abstract class AbstractSvnUpdateIntegrateEnvironment implements UpdateEnvironment {
   protected final SvnVcs myVcs;
@@ -133,13 +134,8 @@ public abstract class AbstractSvnUpdateIntegrateEnvironment implements UpdateEnv
 
     // update switched/ignored status of directories
     private void dirtyRoots() {
-      final Collection<VirtualFile> vfColl = new ArrayList<>(myContentRoots.length);
-      for (FilePath contentRoot: myContentRoots) {
-        final VirtualFile vf = contentRoot.getVirtualFile();
-        if (vf != null) {
-          vfColl.add(vf);
-        }
-      }
+      final Collection<VirtualFile> vfColl = Arrays.stream(myContentRoots).map(FilePath::getVirtualFile)
+        .filter(Objects::nonNull).collect(Collectors.toList());
       myDirtyScopeManager.filesDirty(vfColl, null);
     }
 
diff --git a/xml/dom-openapi/src/com/intellij/util/xml/tree/AbstractDomElementNode.java b/xml/dom-openapi/src/com/intellij/util/xml/tree/AbstractDomElementNode.java
index 0b0be369cd9a..11dcaa5f293f 100644
--- a/xml/dom-openapi/src/com/intellij/util/xml/tree/AbstractDomElementNode.java
+++ b/xml/dom-openapi/src/com/intellij/util/xml/tree/AbstractDomElementNode.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -25,7 +25,9 @@ import com.intellij.util.xml.DomUtil;
 
 import javax.swing.*;
 import java.lang.reflect.Type;
-import java.util.*;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.Optional;
 
 abstract public class AbstractDomElementNode extends SimpleNode {
 
@@ -69,17 +71,9 @@ abstract public class AbstractDomElementNode extends SimpleNode {
 
     final Class aClass = ReflectionUtil.getRawType(type);
 
-    List<Class> allParents = new ArrayList<>();
-    for (Map.Entry<Class, Boolean> entry : hiders.entrySet()) {
-      if (entry.getKey().isAssignableFrom(aClass)) {
-        allParents.add(entry.getKey());
-      }
-    }
-    if (allParents.size() == 0) return false;
-
-    Collections.sort(allParents, INHERITORS_COMPARATOR);
-
-    return hiders.get(allParents.get(0)).booleanValue();
+    Optional<Class> parent = hiders.keySet().stream()
+      .filter(klass -> klass.isAssignableFrom(aClass)).min(INHERITORS_COMPARATOR);
+    return parent.map(hiders::get).orElse(false);
 
   }
 
diff --git a/xml/impl/src/com/intellij/xml/config/ConfigFilesTreeBuilder.java b/xml/impl/src/com/intellij/xml/config/ConfigFilesTreeBuilder.java
index 31c41aa6d828..62b91f4b4a34 100644
--- a/xml/impl/src/com/intellij/xml/config/ConfigFilesTreeBuilder.java
+++ b/xml/impl/src/com/intellij/xml/config/ConfigFilesTreeBuilder.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2015 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -136,12 +136,9 @@ public class ConfigFilesTreeBuilder {
     return fileType.getName() + " context files" ;
   }
 
-  private boolean hasNonEmptyGroups(MultiMap<FileType, PsiFile> filesByType) {
-    byte nonEmptyGroups = 0;
-    for (Map.Entry<FileType, Collection<PsiFile>> entry : filesByType.entrySet()) {
-      Collection<PsiFile> files = entry.getValue();
-      if (files != null && files.size() > 0) nonEmptyGroups++;
-    }
+  private static boolean hasNonEmptyGroups(MultiMap<FileType, PsiFile> filesByType) {
+    long nonEmptyGroups = filesByType.entrySet().stream().map(Map.Entry::getValue)
+      .filter(files -> files != null && !files.isEmpty()).limit(2).count();
     return nonEmptyGroups > 1;
   }
 
diff --git a/xml/xml-psi-impl/src/com/intellij/psi/impl/source/xml/XmlTagValueImpl.java b/xml/xml-psi-impl/src/com/intellij/psi/impl/source/xml/XmlTagValueImpl.java
index 21eef0105f6c..45c5373a225c 100644
--- a/xml/xml-psi-impl/src/com/intellij/psi/impl/source/xml/XmlTagValueImpl.java
+++ b/xml/xml-psi-impl/src/com/intellij/psi/impl/source/xml/XmlTagValueImpl.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2014 JetBrains s.r.o.
+ * Copyright 2000-2016 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -29,6 +29,7 @@ import com.intellij.util.containers.ContainerUtil;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 
 public class XmlTagValueImpl implements XmlTagValue{
@@ -56,11 +57,10 @@ public class XmlTagValueImpl implements XmlTagValue{
   public XmlText[] getTextElements() {
     XmlText[] textElements = myTextElements;
     if(textElements != null) return textElements;
-    final List<XmlText> textElementsList = new ArrayList<>();
-    for (final XmlTagChild element : myElements) {
-      if (element instanceof XmlText) textElementsList.add((XmlText)element);
-    }
-    return myTextElements = textElementsList.isEmpty() ? XmlText.EMPTY_ARRAY : ContainerUtil.toArray(textElementsList, new XmlText[textElementsList.size()]);
+    myTextElements = Arrays.stream(myElements)
+      .filter(element -> element instanceof XmlText)
+      .map(element -> (XmlText)element).toArray(XmlText[]::new);
+    return myTextElements;
   }
 
   @Override