Index: trunk/src/org/openstreetmap/josm/data/osm/Changeset.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/Changeset.java	(revision 11114)
+++ trunk/src/org/openstreetmap/josm/data/osm/Changeset.java	(revision 11115)
@@ -208,9 +208,10 @@
     public void setKeys(Map<String, String> keys) {
         CheckParameterUtil.ensureParameterNotNull(keys, "keys");
-        for (String value : keys.values()) {
-            if (value != null && value.length() > MAX_CHANGESET_TAG_LENGTH) {
+        keys.values().stream()
+                .filter(value -> (value != null && value.length() > MAX_CHANGESET_TAG_LENGTH))
+                .findFirst()
+                .ifPresent(value -> {
                 throw new IllegalArgumentException("Changeset tag value is too long: "+value);
-            }
-        }
+        });
         this.tags = keys;
     }
Index: trunk/src/org/openstreetmap/josm/data/osm/ChangesetCache.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/ChangesetCache.java	(revision 11114)
+++ trunk/src/org/openstreetmap/josm/data/osm/ChangesetCache.java	(revision 11115)
@@ -10,4 +10,5 @@
 import java.util.Set;
 import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.stream.Collectors;
 
 import org.openstreetmap.josm.Main;
@@ -183,11 +184,7 @@
      */
     public List<Changeset> getOpenChangesets() {
-        List<Changeset> ret = new ArrayList<>();
-        for (Changeset cs: cache.values()) {
-            if (cs.isOpen()) {
-                ret.add(cs);
-            }
-        }
-        return ret;
+        return cache.values().stream()
+                .filter(Changeset::isOpen)
+                .collect(Collectors.toList());
     }
 
Index: trunk/src/org/openstreetmap/josm/data/osm/ChangesetDataSet.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/ChangesetDataSet.java	(revision 11114)
+++ trunk/src/org/openstreetmap/josm/data/osm/ChangesetDataSet.java	(revision 11115)
@@ -3,9 +3,9 @@
 
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 import org.openstreetmap.josm.data.osm.history.HistoryOsmPrimitive;
@@ -117,11 +117,8 @@
     public Set<HistoryOsmPrimitive> getPrimitivesByModificationType(ChangesetModificationType cmt) {
         CheckParameterUtil.ensureParameterNotNull(cmt, "cmt");
-        Set<HistoryOsmPrimitive> ret = new HashSet<>();
-        for (Entry<PrimitiveId, ChangesetModificationType> entry: modificationTypes.entrySet()) {
-            if (entry.getValue().equals(cmt)) {
-                ret.add(primitives.get(entry.getKey()));
-            }
-        }
-        return ret;
+        return modificationTypes.entrySet().stream()
+                .filter(entry -> entry.getValue().equals(cmt))
+                .map(entry -> primitives.get(entry.getKey()))
+                .collect(Collectors.toSet());
     }
 
Index: trunk/src/org/openstreetmap/josm/data/osm/DataSet.java
===================================================================
--- trunk/src/org/openstreetmap/josm/data/osm/DataSet.java	(revision 11114)
+++ trunk/src/org/openstreetmap/josm/data/osm/DataSet.java	(revision 11115)
@@ -21,4 +21,5 @@
 import java.util.concurrent.locks.ReentrantReadWriteLock;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 
 import org.openstreetmap.josm.Main;
@@ -420,11 +421,7 @@
         try {
             // QuadBuckets might be useful here (don't forget to do reindexing after some of rm is changed)
-            List<Relation> result = new ArrayList<>();
-            for (Relation r: relations) {
-                if (r.getBBox().intersects(bbox)) {
-                    result.add(r);
-                }
-            }
-            return result;
+            return relations.stream()
+                    .filter(r -> r.getBBox().intersects(bbox))
+                    .collect(Collectors.toList());
         } finally {
             lock.readLock().unlock();
Index: trunk/src/org/openstreetmap/josm/gui/conflict/pair/ListMergeModel.java
===================================================================
--- trunk/src/org/openstreetmap/josm/gui/conflict/pair/ListMergeModel.java	(revision 11114)
+++ trunk/src/org/openstreetmap/josm/gui/conflict/pair/ListMergeModel.java	(revision 11115)
@@ -226,9 +226,9 @@
         synchronized (listeners) {
             PropertyChangeEvent evt = new PropertyChangeEvent(this, FROZEN_PROP, oldValue, newValue);
-            for (PropertyChangeListener listener: listeners) {
+            listeners.forEach((listener) -> {
                 listener.propertyChange(evt);
+            });
             }
         }
-    }
 
     public final void setFrozen(boolean isFrozen) {
@@ -678,9 +678,6 @@
             if (row >= getEntries().size()) return false;
             T e1 = getEntries().get(row);
-            for (T e2: getOppositeEntries()) {
-                if (isEqualEntry(e1, e2)) return true;
+            return getOppositeEntries().stream().anyMatch(e2 -> isEqualEntry(e1, e2));
             }
-            return false;
-        }
 
         protected List<T> getEntries() {