Fixed findbugs warnings.

src/main/java/org/orekit/data/ZipJarCrawler.java

@@ -288,6 +288,10 @@ public class ZipJarCrawler implements DataProvider {
                 /** {@inheritDoc} */
                 @Override
                 public EntryStream next() throws NoSuchElementException {
+                    if (next == null) {
+                        // this should never happen
+                        throw new NoSuchElementException();
+                    }
                     return next;
                 }
 

src/main/java/org/orekit/estimation/measurements/Range.java

@@ -162,8 +162,8 @@ public class Range extends AbstractMeasurement<Range> {
             dRdPx * dt, dRdPy * dt, dRdPz * dt
         });
 
-        if (station.getEastOffsetDriver().isSelected()  |
-            station.getNorthOffsetDriver().isSelected() |
+        if (station.getEastOffsetDriver().isSelected()  ||
+            station.getNorthOffsetDriver().isSelected() ||
             station.getZenithOffsetDriver().isSelected()) {
 
             // donwlink partial derivatives

src/main/java/org/orekit/propagation/integration/IntegratedEphemeris.java

@@ -187,11 +187,7 @@ public class IntegratedEphemeris
             }
             return state;
         } catch (OrekitExceptionWrapper oew) {
-            if (oew.getException() instanceof OrekitException) {
-                throw (OrekitException) oew.getException();
-            } else {
-                throw new OrekitException(oew.getException());
-            }
+            throw oew.getException();
         }
     }