Correct "bugs" found with FindBugs.

src/main/java/com/yahoo/sketches/memory/UnsafeUtil.java

@@ -6,6 +6,7 @@
 package com.yahoo.sketches.memory;
 
 import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
 
 import com.yahoo.sketches.SketchesException;
 
@@ -70,18 +71,25 @@ final class UnsafeUtil {
   static final long UNSAFE_COPY_THRESHOLD = 1L << 20; //2^20
 
   static {
-    try {
-      //should work across JVMs, e.g., with Android:
-      Constructor<Unsafe> unsafeConstructor = Unsafe.class.getDeclaredConstructor();
-      unsafeConstructor.setAccessible(true);
-      unsafe = unsafeConstructor.newInstance();
-
-      // Alternative, but may not work across different JVMs.
-//    Field field = Unsafe.class.getDeclaredField("theUnsafe");
-//    field.setAccessible(true);
-//    unsafe = (Unsafe) field.get(null);
-
-      //4 on 32-bits systems, 8 on 64-bit systems.  Not an indicator of compressed ref (Oop)
+      try {
+        //should work across JVMs, e.g., with Android:
+        Constructor<Unsafe> unsafeConstructor = Unsafe.class.getDeclaredConstructor();
+        unsafeConstructor.setAccessible(true);
+        unsafe = unsafeConstructor.newInstance();
+
+        // Alternative, but may not work across different JVMs.
+//      Field field = Unsafe.class.getDeclaredField("theUnsafe");
+//      field.setAccessible(true);
+//      unsafe = (Unsafe) field.get(null);
+
+      } catch (InstantiationException | IllegalAccessException | IllegalArgumentException
+          | InvocationTargetException | NoSuchMethodException e) {
+        e.printStackTrace();
+        throw new SketchesException("Unable to acquire Unsafe. ", e);
+      }
+
+      //4 on 32-bits systems and 64-bit systems < 32GB, otherwise 8.  
+      //This alone is not an indicator of compressed ref (Oop)
       ADDRESS_SIZE = unsafe.addressSize(); 
 
       ARRAY_BOOLEAN_BASE_OFFSET = unsafe.arrayBaseOffset(boolean[].class);
@@ -103,11 +111,6 @@ final class UnsafeUtil {
       ARRAY_FLOAT_INDEX_SCALE = unsafe.arrayIndexScale(float[].class);
       ARRAY_DOUBLE_INDEX_SCALE = unsafe.arrayIndexScale(double[].class);
       ARRAY_OBJECT_INDEX_SCALE = unsafe.arrayIndexScale(Object[].class);
-
-    }
-    catch (Exception e) {
-      throw new SketchesException("Unable to acquire Unsafe. ", e);
-    }
   }
 
   private UnsafeUtil() {}

src/main/java/com/yahoo/sketches/theta/SetOperation.java

@@ -170,13 +170,8 @@ static final int computeMinLgArrLongsFromCount(final int count) {
    */
   static boolean isValidSetOpID(int id) {
     Family family = Family.idToFamily(id);
-    boolean ret;
-    switch (family) {
-      case UNION :
-      case INTERSECTION :
-      case A_NOT_B : ret = true; break;
-      default: ret = false; break;
-    }
+    boolean ret = ((family == Family.UNION) || (family == Family.INTERSECTION) 
+        || (family == Family.A_NOT_B));
     return ret;
   }
 }

src/test/java/com/yahoo/sketches/memory/MemoryMappedFileTest.java

@@ -8,11 +8,13 @@
 import static org.testng.Assert.assertEquals;
 import static org.testng.Assert.assertTrue;
 import static org.testng.Assert.fail;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import java.io.CharArrayReader;
 import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.PrintWriter;
+import java.io.UnsupportedEncodingException;
 
 import org.testng.annotations.Test;
 
@@ -25,7 +27,7 @@ public class MemoryMappedFileTest {
   @Test(expectedExceptions = RuntimeException.class)
   public void testMapException() throws Exception {
     File dummy = createFile("dummy.txt", "");
-    Memory mmf = new MemoryMappedFile(dummy, 0, dummy.length()); //zero length
+    new MemoryMappedFile(dummy, 0, dummy.length()); //zero length
   }
 
   @SuppressWarnings("unused")
@@ -154,7 +156,7 @@ public void testForce() throws Exception {
 
       // add content
       String cor = "Correcting spelling mistakes";
-      byte[] b = cor.getBytes();
+      byte[] b = cor.getBytes(UTF_8);
       mmf.putByteArray(0, b, 0, b.length);
 
       mmf.force();
@@ -193,13 +195,17 @@ public void checkPassThrough() {
     mem.freeMemory();
   }
 
-  @SuppressWarnings("resource")
   private static File createFile(String fileName, String text) throws FileNotFoundException {
     File file = new File(fileName);
     file.deleteOnExit();
-    PrintWriter writer = new PrintWriter(file);
-    writer.print(text);
-    writer.close();
+    PrintWriter writer;
+    try {
+      writer = new PrintWriter(file, UTF_8.name());
+      writer.print(text);
+      writer.close();
+    } catch (UnsupportedEncodingException e) {
+      e.printStackTrace();
+    }
     return file;
   }