Minor Description
Final fields are automatically thread safe if the object itself is not modified.
Whereas non-final fields are not necessarily thread-safe even if they are not mutated - this is because of the Java memory model.
There are several non-final fields that are not mutated once created. They should be made final to improve thread-safety. This is particularly important for static fields since they are more likely to be used by multiple threads.
Note: such changes will not affect the public API if the fields are private or package-protected.
The fields include:
JavaSecureRandom.instance
OpensslSecureRandom.fallback
OpensslSecureRandom.nativeEnabled
ChannelInput.channel
StreamInput.buf - since no point creating an instance if it is not going to be used for reading, might as well create the buffer up front
StreamOutput.bufferSize
StreamOutput.buf - as for StreamInput
StreamOutput.out - should also be private
static NativeCodeLoader.nativeCodeLoaded
static OSInfo.archMapping
static ReflectionUtils.classLoader