diff --git a/src/main/java/com/verisignlabs/dnssec/security/BINDKeyUtils.java b/src/main/java/com/verisignlabs/dnssec/security/BINDKeyUtils.java
index 450f8d4..c9a00d1 100644
--- a/src/main/java/com/verisignlabs/dnssec/security/BINDKeyUtils.java
+++ b/src/main/java/com/verisignlabs/dnssec/security/BINDKeyUtils.java
@@ -46,7 +46,8 @@ import org.xbill.DNS.utils.base64;
  */
 public class BINDKeyUtils {
 
-  private BINDKeyUtils() { }
+  private BINDKeyUtils() {
+  }
 
   /**
    * Calculate the BIND9 key file base name (i.e., without the ".key" or
@@ -60,18 +61,18 @@ public class BINDKeyUtils {
   /** Reads in the DNSKEYRecord from the public key file */
   private static DNSKEYRecord loadPublicKeyFile(File publicKeyFile)
       throws IOException {
-    Master m = new Master(publicKeyFile.getAbsolutePath(), null, 600);
+    try (Master m = new Master(publicKeyFile.getAbsolutePath(), null, 600)) {
+      Record r;
+      DNSKEYRecord result = null;
 
-    Record r;
-    DNSKEYRecord result = null;
-
-    while ((r = m.nextRecord()) != null) {
-      if (r.getType() == Type.DNSKEY) {
-        result = (DNSKEYRecord) r;
+      while ((r = m.nextRecord()) != null) {
+        if (r.getType() == Type.DNSKEY) {
+          result = (DNSKEYRecord) r;
+        }
       }
-    }
 
-    return result;
+      return result;
+    }
   }
 
   /** Reads in the private key verbatim from the private key file */
@@ -272,7 +273,7 @@ public class BINDKeyUtils {
     try {
       DnsKeyConverter conv = new DnsKeyConverter();
       return conv.parsePrivateKeyString(privateKeyString);
-    } catch (IOException|NoSuchAlgorithmException e) {
+    } catch (IOException | NoSuchAlgorithmException e) {
       e.printStackTrace();
     }
 
diff --git a/src/main/java/com/verisignlabs/dnssec/security/TypeMap.java b/src/main/java/com/verisignlabs/dnssec/security/TypeMap.java
index 84542cd..d4a8bea 100644
--- a/src/main/java/com/verisignlabs/dnssec/security/TypeMap.java
+++ b/src/main/java/com/verisignlabs/dnssec/security/TypeMap.java
@@ -37,7 +37,7 @@ public class TypeMap {
   private Set<Integer> typeSet;
 
   public TypeMap() {
-    this.typeSet = new HashSet<Integer>();
+    this.typeSet = new HashSet<>();
   }
 
   /** Add the given type to the typemap. */
@@ -78,20 +78,20 @@ public class TypeMap {
     TypeMap typemap = new TypeMap();
 
     int page;
-    int byte_length;
+    int byteLength;
 
     while (m < map.length) {
       page = map[m++];
-      byte_length = map[m++];
+      byteLength = map[m++];
 
-      for (int i = 0; i < byte_length; i++) {
+      for (int i = 0; i < byteLength; i++) {
         for (int j = 0; j < 8; j++) {
-          if ((map[m + i] & (1 << (7 - j))) != 0) {
+          if (((map[m + i] & 0xFF) & (1 << (7 - j))) != 0) {
             typemap.set((page << 8) + (i * 8) + j);
           }
         }
       }
-      m += byte_length;
+      m += byteLength;
     }
 
     return typemap;
@@ -115,7 +115,7 @@ public class TypeMap {
     int[] types = getTypes();
     Arrays.sort(types);
 
-    StringBuffer sb = new StringBuffer();
+    StringBuilder sb = new StringBuilder();
 
     for (int i = 0; i < types.length; i++) {
       if (i > 0)
@@ -129,16 +129,16 @@ public class TypeMap {
   protected static void mapToWire(DNSOutput out, int[] types, int base, int start, int end) {
     // calculate the length of this map by looking at the largest
     // typecode in this section.
-    int max_type = types[end - 1] & 0xFF;
-    int map_length = (max_type / 8) + 1;
+    int maxType = types[end - 1] & 0xFF;
+    int mapLength = (maxType / 8) + 1;
 
     // write the map "header" -- the base and the length of the map.
     out.writeU8(base & 0xFF);
-    out.writeU8(map_length & 0xFF);
+    out.writeU8(mapLength & 0xFF);
 
     // allocate a temporary scratch space for caculating the actual
     // bitmap.
-    byte[] map = new byte[map_length];
+    byte[] map = new byte[mapLength];
 
     // for each type in our sub-array, set its corresponding bit in the map.
     for (int i = start; i < end; i++) {
@@ -179,7 +179,7 @@ public class TypeMap {
   }
 
   public int[] getTypes() {
-    Integer[] a = (Integer[]) typeSet.toArray(integerArray);
+    Integer[] a = typeSet.toArray(integerArray);
 
     int[] res = new int[a.length];
     for (int i = 0; i < res.length; i++) {
@@ -189,8 +189,8 @@ public class TypeMap {
     return res;
   }
 
-  public static int[] fromWireToTypes(byte[] wire_fmt) {
-    return TypeMap.fromBytes(wire_fmt).getTypes();
+  public static int[] fromWireToTypes(byte[] wireFmt) {
+    return TypeMap.fromBytes(wireFmt).getTypes();
   }
 
   public static byte[] fromTypesToWire(int[] types) {
diff --git a/src/main/java/com/verisignlabs/dnssec/security/ZoneUtils.java b/src/main/java/com/verisignlabs/dnssec/security/ZoneUtils.java
index 209c27d..5729197 100644
--- a/src/main/java/com/verisignlabs/dnssec/security/ZoneUtils.java
+++ b/src/main/java/com/verisignlabs/dnssec/security/ZoneUtils.java
@@ -39,6 +39,10 @@ import org.xbill.DNS.Type;
  */
 
 public class ZoneUtils {
+
+  private ZoneUtils() {
+  }
+
   /**
    * Load a zone file.
    *
@@ -53,19 +57,10 @@ public class ZoneUtils {
    *                     if something goes wrong reading the zone file.
    */
   public static List<Record> readZoneFile(String zonefile, Name origin) throws IOException {
-    ArrayList<Record> records = new ArrayList<Record>();
-    Master m;
-    try {
-      if (zonefile.equals("-")) {
-        m = new Master(System.in);
-      } else {
-        m = new Master(zonefile, origin);
-      }
-
+    ArrayList<Record> records = new ArrayList<>();
+    try (Master m = zonefile.equals("-") ? new Master(System.in) : new Master(zonefile, origin)) {
       Record r = null;
-
       while ((r = m.nextRecord()) != null) {
-
         records.add(r);
       }
     } catch (IOException e) {
@@ -120,7 +115,7 @@ public class ZoneUtils {
   }
 
   public static List<Record> findRRs(List<Record> records, Name name, int type) {
-    List<Record> res = new ArrayList<Record>();
+    List<Record> res = new ArrayList<>();
     for (Record r : records) {
       if (r.getName().equals(name) && r.getType() == type) {
         res.add(r);