關鍵字 (keyword) 為具有語法功能的保留字 (reserved word) ,Java 的關鍵字共有 50 個,如以下列表
abstract | continue | for | new | switch |
assert*** | default | goto* | package | synchronized |
boolean | do | if | private | this |
break | double | implements | protected | throw |
byte | else | import | public | throws |
case | enum**** | instanceof | return | transient |
catch | extends | int | short | try |
char | final | interface | static | void |
class | finally | long | strictfp** | volatile |
const* | float | native | super | while |