関連ワード:  java 21 or java 8    java 17 21 or java 8    java 21 vs java 8    java 21 vs java 8 performance    java 21 and java 8 difference    java 21 vs java 8 minecraft    java 21 vs java 8 features    java 21 compile java 8    java 21 target java 8    jdk 21 java 8