Index: src/uk/me/parabola/mkgmap/reader/osm/xml/Osm5XmlHandler.java
===================================================================
--- src/uk/me/parabola/mkgmap/reader/osm/xml/Osm5XmlHandler.java	(revision 1479)
+++ src/uk/me/parabola/mkgmap/reader/osm/xml/Osm5XmlHandler.java	(working copy)
@@ -46,6 +46,7 @@
 import uk.me.parabola.mkgmap.general.RoadNetwork;
 import uk.me.parabola.mkgmap.reader.osm.CoordPOI;
 import uk.me.parabola.mkgmap.reader.osm.Element;
+import uk.me.parabola.mkgmap.reader.osm.FakeIdGenerator;
 import uk.me.parabola.mkgmap.reader.osm.GeneralRelation;
 import uk.me.parabola.mkgmap.reader.osm.MultiPolygonRelation;
 import uk.me.parabola.mkgmap.reader.osm.Node;
@@ -92,8 +93,6 @@
 
 	private static final long CYCLEWAY_ID_OFFSET = 0x10000000;
 
-	private static final long FAKE_ID_BASE = 1L << 62;
-
 	private Node currentNode;
 	private Way currentWay;
 	private Node currentNodeInWay;
@@ -106,8 +105,6 @@
 	private Area bbox;
 	private Runnable endTask;
 
-	private long nextFakeId = 1;
-
 	private final boolean reportUndefinedNodes;
 	private final boolean makeOppositeCycleways;
 	private final boolean makeCycleways;
@@ -1054,14 +1051,6 @@
 		super.fatalError(e);
 	}
 
-	public long makeFakeId() {
-		return FAKE_ID_BASE + nextFakeId++;
-	}
-
-	public boolean isFakeId(long id) {
-		return id >= FAKE_ID_BASE;
-	}
-
 	private long idVal(String id) {
 		try {
 			// attempt to parse id as a number
@@ -1071,7 +1060,7 @@
 			// if that fails, fake a (hopefully) unique value
 			Long fakeIdVal = fakeIdMap.get(id);
 			if(fakeIdVal == null) {
-				fakeIdVal = makeFakeId();
+				fakeIdVal = FakeIdGenerator.getFakeId();
 				fakeIdMap.put(id, fakeIdVal);
 			}
 			//System.out.printf("%s = 0x%016x\n", id, fakeIdVal);
@@ -1096,7 +1085,7 @@
 				log.info("clipping " + segment);
 				toBeRemoved.add(segment);
 				for (List<Coord> pts : clipped) {
-					long id = makeFakeId();
+					long id = FakeIdGenerator.getFakeId();
 					Way shore = new Way(id, pts);
 					toBeAdded.add(shore);
 				}
@@ -1123,7 +1112,7 @@
 				// polygon so that the tile's background colour will
 				// match the land colour on the tiles that do contain
 				// some sea
-				long landId = makeFakeId();
+				long landId = FakeIdGenerator.getFakeId();
 				Way land = new Way(landId);
 				land.addPoint(nw);
 				land.addPoint(sw);
@@ -1137,7 +1126,7 @@
 			return;
 		}
 
-		long multiId = makeFakeId();
+		long multiId = FakeIdGenerator.getFakeId();
 		Relation seaRelation = null;
 		if(generateSeaUsingMP) {
 			seaRelation = new GeneralRelation(multiId);
@@ -1173,8 +1162,8 @@
 			if(generateSeaUsingMP)
 				seaRelation.addElement("inner", w);
 			else {
-				if(!isFakeId(w.getId())) {
-					Way w1 = new Way(makeFakeId());
+				if(!FakeIdGenerator.isFakeId(w.getId())) {
+					Way w1 = new Way(FakeIdGenerator.getFakeId());
 					w1.getPoints().addAll(w.getPoints());
 					// only copy the name tags
 					for(String tag : w)
@@ -1233,8 +1222,8 @@
 					if(generateSeaUsingMP)
 						seaRelation.addElement("inner", w);
 					else {
-						if(!isFakeId(w.getId())) {
-							Way w1 = new Way(makeFakeId());
+						if(!FakeIdGenerator.isFakeId(w.getId())) {
+							Way w1 = new Way(FakeIdGenerator.getFakeId());
 							w1.getPoints().addAll(w.getPoints());
 							// only copy the name tags
 							for(String tag : w)
@@ -1247,7 +1236,7 @@
 					}
 				}
 				else if(allowSeaSectors) {
-					seaId = makeFakeId();
+					seaId = FakeIdGenerator.getFakeId();
 					sea = new Way(seaId);
 					sea.getPoints().addAll(points);
 					sea.addPoint(new Coord(pEnd.getLatitude(), pStart.getLongitude()));
@@ -1273,7 +1262,7 @@
 			}
 		}
 		if (generateSeaBackground) {
-			seaId = makeFakeId();
+			seaId = FakeIdGenerator.getFakeId();
 			sea = new Way(seaId);
 			sea.addPoint(nw);
 			sea.addPoint(sw);
@@ -1290,7 +1279,7 @@
 		// now construct inner ways from these segments
 		NavigableSet<EdgeHit> hits = (NavigableSet<EdgeHit>) hitMap.keySet();
 		while (!hits.isEmpty()) {
-			long id = makeFakeId();
+			long id = FakeIdGenerator.getFakeId();
 			Way w = new Way(id);
 			wayMap.put(id, w);
 
@@ -1350,8 +1339,8 @@
 			if(generateSeaUsingMP)
 				seaRelation.addElement("inner", w);
 			else {
-				if(!isFakeId(w.getId())) {
-					Way w1 = new Way(makeFakeId());
+				if(!FakeIdGenerator.isFakeId(w.getId())) {
+					Way w1 = new Way(FakeIdGenerator.getFakeId());
 					w1.getPoints().addAll(w.getPoints());
 					for(String tag : w)
 						if(tag.equals("name") || tag.endsWith(":name"))
@@ -1483,8 +1472,8 @@
 					log.info("merging: ", ways.size(), w1.getId(), w2.getId());
 					List<Coord> points2 = w2.getPoints();
 					Way wm;
-					if (!isFakeId(w1.getId())) {
-						wm = new Way(makeFakeId());
+					if (!FakeIdGenerator.isFakeId(w1.getId())) {
+						wm = new Way(FakeIdGenerator.getFakeId());
 						ways.remove(w1);
 						ways.add(wm);
 						wm.getPoints().addAll(points1);
Index: src/uk/me/parabola/mkgmap/reader/osm/FakeIdGenerator.java
===================================================================
--- src/uk/me/parabola/mkgmap/reader/osm/FakeIdGenerator.java	(revision 0)
+++ src/uk/me/parabola/mkgmap/reader/osm/FakeIdGenerator.java	(revision 0)
@@ -0,0 +1,24 @@
+package uk.me.parabola.mkgmap.reader.osm;
+
+import java.util.concurrent.atomic.AtomicLong;
+
+public class FakeIdGenerator {
+
+	public static final long START_ID = 1L << 62;
+	
+	private static final AtomicLong fakeId = new AtomicLong(START_ID);
+
+	/**
+	 * Retrieves a unique id that can be used to fake OSM ids.
+	 * 
+	 * @return a unique id
+	 */
+	public static long getFakeId() {
+		return fakeId.incrementAndGet();
+	}
+
+	public static boolean isFakeId(long id) {
+		return id >= START_ID;
+	}
+	
+}