This explains you what happens if we add unique custom objects as keys to a HashMap and we wish to identify unique key for this HashMap. Overriding of equals and hashcode should go together. If 2 ...

**You must override hashCode in every class that overrides equals.** If you fail to do so, your class will violate the general contract for hashCode, which will prevent it from functioning properly in ...

拙者、Javaの奥儀百箇条をここに伝授仕る所存！この書、プログラムを極めんとする者、またSilver資格を目指す者にこそ読むべき巻物なり。是非とも手に取られよ！ Java 7 以降、switch 文は String を受け付けるようになった。 この際、内部では hashCode() を用いて ...