Fixed findbugs warnings.

src/main/java/org/orekit/rugged/api/SensorPixelCrossing.java

@@ -35,7 +35,7 @@ import org.orekit.time.AbsoluteDate;
 class SensorPixelCrossing {
 
     /** Margin before and after end pixels, in order to avoid search failures near boundaries. */
-    private final double MARGIN = 5.0;
+    private static final double MARGIN = 5.0;
 
     /** Line sensor. */
     private final LineSensor sensor;

src/main/java/org/orekit/rugged/raster/TilesCache.java

@@ -16,6 +16,7 @@
  */
 package org.orekit.rugged.raster;
 
+import java.io.Serializable;
 import java.lang.reflect.Array;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -341,7 +342,10 @@ public class TilesCache<T extends Tile> {
     }
 
     /** Comparator for sorting with respect to latitude. */
-    private static class LatitudeComparator implements Comparator<LatitudeProvider> {
+    private static class LatitudeComparator implements Comparator<LatitudeProvider>, Serializable {
+
+        /** Serializable UID. */
+        private static final long serialVersionUID = 20141212L;
 
         /** {@inheritDoc} */
         @Override
@@ -352,7 +356,10 @@ public class TilesCache<T extends Tile> {
     }
 
     /** Comparator for sorting with respect to longitude. */
-    private static class LongitudeComparator implements Comparator<LongitudeProvider> {
+    private static class LongitudeComparator implements Comparator<LongitudeProvider>, Serializable {
+
+        /** Serializable UID. */
+        private static final long serialVersionUID = 20141212L;
 
         /** {@inheritDoc} */
         @Override

src/main/java/org/orekit/rugged/utils/NormalizedGeodeticPoint.java

@@ -55,4 +55,20 @@ public class NormalizedGeodeticPoint extends GeodeticPoint {
         return normalizedLongitude;
     }
 
+    /** {@inheritDoc} */
+    @Override
+    public boolean equals(final Object object) {
+        // we override the method just to make it clear that we INTENTIONALLY
+        // consider normalized point are just similar to regular points
+        return super.equals(object);
+    }
+
+    /** {@inheritDoc} */
+    @Override
+    public int hashCode() {
+        // we override the method just to make it clear that we INTENTIONALLY
+        // consider normalized point are just similar to regular points
+        return super.hashCode();
+    }
+
 }