Fix unbalanced <p> tags in JavaDocs.

core/src/main/java/org/bitcoinj/core/AlertMessage.java

@@ -31,7 +31,7 @@ import java.util.Set;
  * log, email), or if you decide to use alerts for notifications that are specific to your app in some way, to parse it.
  * For example, you could treat it as an upgrade notification specific to your app. Satoshi designed alerts to ensure
  * that software upgrades could be distributed independently of a hard-coded website, in order to allow everything to
- * be purely peer-to-peer. You don't have to use this of course, and indeed it often makes more sense not to.<p>
+ * be purely peer-to-peer. You don't have to use this of course, and indeed it often makes more sense not to.</p>
  *     
  * <p>Before doing anything with an alert, you should check {@link AlertMessage#isSignatureValid()}.</p>
  * 

core/src/main/java/org/bitcoinj/store/LevelDBFullPrunedBlockStore.java

@@ -56,7 +56,7 @@ import com.google.common.collect.Lists;
 /**
  * <p>
  * An implementation of a Fully Pruned Block Store using a leveldb implementation as the backing data store.
- * <p>
+ * </p>
  * 
  * <p>
  * Includes number of caches to optimise the initial blockchain download.