Findbugs all over #4

apps/routerconsole/jsp/error500.jsp

...va/src/net/i2p/client/naming/SingleFileNamingService.java

core/java/src/net/i2p/stat/RateStat.java

core/java/src/net/i2p/util/HexDump.java

core/java/src/net/i2p/util/LogRecordFormatter.java

router/java/src/net/i2p/router/peermanager/DBHistory.java

.../net/i2p/router/peermanager/ProfilePersistenceHelper.java

...er/java/src/net/i2p/router/peermanager/TunnelHistory.java

router/java/src/net/i2p/router/startup/WorkingDir.java

router/java/src/net/i2p/router/tasks/MarkLiveliness.java