Address comments from Miron and Andreas:

- Make GetBlocksMessage/GetHeadersMessage implement toString/hashCode
- Minor comment/naming fixes
- > not >= for comparing fast catchup time to block header
- Return current time in Wallet.getEarliestKeyCreationTime() rather than throw an exception when there are no keys in the wallet.

src/com/google/bitcoin/core/GetBlocksMessage.java

@@ -23,9 +23,9 @@ import java.util.List;
 
 public class GetBlocksMessage extends Message {
     private static final long serialVersionUID = 3479412877853645644L;
-    private long version;
-    private List<Sha256Hash> locator;
-    private Sha256Hash stopHash;
+    protected long version;
+    protected List<Sha256Hash> locator;
+    protected Sha256Hash stopHash;
 
     public GetBlocksMessage(NetworkParameters params, List<Sha256Hash> locator, Sha256Hash stopHash) {
         super(params);
@@ -83,4 +83,21 @@ public class GetBlocksMessage extends Message {
         // Next, a block ID to stop at.
         stream.write(stopHash.getBytes());
     }
+
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof GetBlocksMessage)) return false;
+        GetBlocksMessage other = (GetBlocksMessage) o;
+        return (other.version == version &&
+                locator.size() == other.locator.size() && locator.containsAll(other.locator) &&
+                stopHash.equals(other.stopHash));
+    }
+
+    @Override
+    public int hashCode() {
+        int hashCode = (int) version ^ "getblocks".hashCode();
+        for (int i = 0; i < locator.size(); i++) hashCode ^= locator.get(i).hashCode();
+        hashCode ^= stopHash.hashCode();
+        return hashCode;
+    }
 }

src/com/google/bitcoin/core/GetHeadersMessage.java

@@ -28,4 +28,36 @@ public class GetHeadersMessage extends GetBlocksMessage {
     public GetHeadersMessage(NetworkParameters params, List<Sha256Hash> locator, Sha256Hash stopHash) {
         super(params, locator, stopHash);
     }
+
+    @Override
+    public String toString() {
+        StringBuffer b = new StringBuffer();
+        b.append("getheaders: ");
+        for (Sha256Hash hash : locator) {
+            b.append(hash.toString());
+            b.append(" ");
+        }
+        return b.toString();
+    }
+
+    /**
+     * Compares two getheaders messages. Note that even though they are structurally identical a GetHeadersMessage
+     * will not compare equal to a GetBlocksMessage containing the same data.
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (!(o instanceof GetHeadersMessage)) return false;
+        GetHeadersMessage other = (GetHeadersMessage) o;
+        return (other.version == version &&
+                locator.size() == other.locator.size() && locator.containsAll(other.locator) &&
+                stopHash.equals(other.stopHash));
+    }
+
+    @Override
+    public int hashCode() {
+        int hashCode = (int) version ^ "getheaders".hashCode();
+        for (int i = 0; i < locator.size(); i++) hashCode ^= locator.get(i).hashCode();
+        hashCode ^= stopHash.hashCode();
+        return hashCode;
+    }
 }

src/com/google/bitcoin/core/Peer.java

@@ -356,7 +356,7 @@ public class Peer {
             fastCatchupTimeSecs = secondsSinceEpoch;
             // If the given time is before the current chains head block time, then this has no effect (we already
             // downloaded everything we need).
-            if (fastCatchupTimeSecs >= blockChain.getChainHead().getHeader().getTimeSeconds()) {
+            if (fastCatchupTimeSecs > blockChain.getChainHead().getHeader().getTimeSeconds()) {
                 downloadBlockBodies = false;
             }
         }
@@ -483,7 +483,7 @@ public class Peer {
             }
             blockLocator.add(0, topBlock.getHash());
         }
-        // The stopHash field is set to zero already by the constructor.
+        // The toHash field is set to zero already by the constructor.
         
         if (downloadBlockBodies) {
             GetBlocksMessage message = new GetBlocksMessage(params, blockLocator, toHash);

src/com/google/bitcoin/core/PeerGroup.java

@@ -453,7 +453,7 @@ public class PeerGroup {
 
     /**
      * Tells the PeerGroup to download only block headers before a certain time and bodies after that. See
-     * {@link Peer#setFastCatchupTime(long)} for further explanation.
+     * {@link Peer#setFastCatchupTime(long)} for further explanation. Call this before starting block chain download.
      */
     public synchronized void setFastCatchupTimeSecs(long secondsSinceEpoch) {
         fastCatchupTimeSecs = secondsSinceEpoch;

src/com/google/bitcoin/core/Wallet.java

@@ -1030,13 +1030,13 @@ public class Wallet implements Serializable {
      * This method is most often used in conjunction with {@link PeerGroup#setFastCatchupTimeSecs(long)} in order to
      * optimize chain download for new users of wallet apps. Backwards compatibility notice: if you get zero from this
      * method, you can instead use the time of the first release of your software, as it's guaranteed no users will
-     * have wallets pre-dating this time.
+     * have wallets pre-dating this time. <p>
      * 
-     * @throws IllegalStateException if there are no keys in the wallet.
+     * If there are no keys in the wallet, the current time is returned.
      */
     public long getEarliestKeyCreationTime() {
         if (keychain.size() == 0) {
-            throw new IllegalStateException("No keys in wallet");
+            return Utils.now().getTime() / 1000;
         }
         long earliestTime = Long.MAX_VALUE;
         for (ECKey key : keychain) {

tests/com/google/bitcoin/core/WalletTest.java

@@ -327,16 +327,14 @@ public class WalletTest {
     @Test
     public void keyCreationTime() throws Exception {
         wallet = new Wallet(params);
-        // No keys throws an exception.
-        try {
-            wallet.getEarliestKeyCreationTime();
-            fail();
-        } catch (IllegalStateException e) {}
         long now = Utils.rollMockClock(0).getTime() / 1000;  // Fix the mock clock.
-        wallet.addKey(new ECKey());
+        // No keys returns current time.
         assertEquals(now, wallet.getEarliestKeyCreationTime());
         Utils.rollMockClock(60);
         wallet.addKey(new ECKey());
-        assertEquals(now, wallet.getEarliestKeyCreationTime());
+        assertEquals(now + 60, wallet.getEarliestKeyCreationTime());
+        Utils.rollMockClock(60);
+        wallet.addKey(new ECKey());
+        assertEquals(now + 60, wallet.getEarliestKeyCreationTime());
     }
 }