Fix findbugs violations in applications

Fix findbugs violations in applications

- Method ignores return value
- Consider using Locale parameterized version of invoked method
- Reliance on default encoding
- Write to static field from instance method
- Inefficient use of keySet iterator instead of entrySet iterator
- Dead store to local variable
- Consider returning a zero length array rather than null
- Consider using Locale parameterized version of invoked method
- Boxing/unboxing to parse a primitive - use parseXXX method
- Unread field
- Dead store to local variable
- Non-transient non-serializable instance field in serializable class
- Parameter must be non-null but is marked as nullable
- Field not initialized in constructor but dereferenced without null check
- Nullcheck of value previously dereferenced
- Redundant nullcheck of value known to be non-null

Change-Id: I1887f775f61fb8e3e6989113edf7faf4f9b06b34
Signed-off-by: Tom Pantelis <tompantelis@gmail.com>