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The ideal time to catch an error is at compile time, before you even try to run the program. However, not all errors can be detected at compile time... 阅读全文
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To solve the general programming problem, you need to create any number of objects, anytime, anywhere. So you can't rely on creating a named referen... 阅读全文
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The inner class is a valuable feature because it allows you to group classes that logically belong together and to control the visibility of one wit... 阅读全文
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Interfaces and abstract classes provide more structured way to separate interface from implementation. the abstract class, which is a kind of midway ... 阅读全文
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Polymorphism is the third essential feature of an object-oriented programming language,after data abastraction and inheritance.It provides another d... 阅读全文
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win 7下C:\Users\Administrator.U5G4L4PUY34SH5C\AppData\Local\Apps\2.0\KPVZOAYK.0JE\56B55RCH.A7A\winr..tion_e7c0311bce13e92e_0001.0000_7144af3298056f4f红色... 阅读全文
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The trick is to use the classes without soiling the existing code. 1. composition--simply create objects of your existing class inside the new class.... 阅读全文
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Access control ( or implementation hiding) is about "not getting it right the first time."refactoringa primary consideration in object-oriented design... 阅读全文
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Two of these safety issues are initialization and cleanup. initialization -> bug cleanup -> running out of resources (most notably, memory) Java ... 阅读全文
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dataType的值不能为"", 否则会导致错误发生：Uncaught TypeError: Cannot read property '0' of null，http请求可以发送，但是callback不能触发 阅读全文