You are probably familiar with the concepts of identity and equality.

您可能熟悉相同性(identity)和相等性(equality)的概念。

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There are two approaches to defining equality and hash value: identity-based, which is the default provided by Object, and state-based, which requires overriding both equals() and hashCode().

有两种方法来定义对象的相等性和散列值：基于标识，它是 Object 提供的缺省方法；基于状态，它要求 Override equals() 和 hashCode() 。

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"America likes to think of itself as a land of equality and opportunity, the so-called American dream is very deep to our sense of identity, " he said.

BBC: Davos 2013: Joseph Stiglitz attacks US 'inequality'