Refactor changes to improve code readability

[prasanth08]

Description

Removed null checks before checking instanceof as null case is handled. Reorder Access modifiers as per JSR standard Use of lambda expression to improve readability.

Motivation

Refactor changes to improve code readability.

[Craigacp]

The null checks & access modifier reorderings are fine, but please don't modify the generated protobuf code (anything in a protos package) as those changes will be overwritten when we regenerate the protobufs as we change protobuf-java versions. In general we leave the public modifier in interfaces to make it explicit even for default methods, so don't remove that either.

[prasanth08]

Got it! Made those changes.

[Craigacp]

Thanks for the contribution.