final --> for primitives --> value can't change. for non-primitives --> you can't change the reference and point it to another object. Note : It is different from immutability.
Hands down, the Bluetooth speaker with the longest battery life is the Fugoo. It offers up to 40 hours of battery life, nearly twice the battery life of other leading Bluetooth speakers in this category. Given how long its battery lasts, you might even forget that the Fugoo needs to be plugged in to charge.
VERDICT / The Altec Life Jacket is one of the most durable and rugged Bluetooth speakers available, and it has a battery that lasts all day. With its industrial design and heavy-duty rubber skin, the Altec Life Jacket is one of the most portable Bluetooth speakers on the market. You can take it almost anywhere. It's resistant to water, impact and dirt.