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If we spoke a different language, we would perceive a somewhat different world. Ludwig Wittgenstein(1889-1951) You manipulate objects with references Although you treat everything as an object, the identifier you manipulate is actually "reference&quo…
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Java Provides a number of ways to hold objects: An array associates numerical indexes to objects. It holds objects of a known type so that you don't have to cast the result when you're looking up an object. It can be multidimensional, and it can hold…
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String 对象是不可修改的,对于被String 重载的'+' 和'+=' 运算符来说,当你用它们来连接两个String 对象的时候,它在底层并不会对于每一次连接均生成一个String 对象,取而代之,在底层会有一个非线程安全的可修改的StringBuilder 对象被构造出来,并且调用其append()方法来生成我们需要拼接的字符串.关于这一点,我们可以随便编写一个字符串拼接语句,然后使用JDK自带的javap 工具,通过javap -c 编译后的类文件名 命令来查看其对应的JVM字节码(相…
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