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A class should represent a single concept from the problem domain, such as business, science, or mathematics.
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2. |
The public interface of a class is cohesive if all of its features are related to the concept that the class represents.
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3. |
A class depends on another class if it uses objects of that class.
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It is a good practice to minimize the coupling (i.e., dependency) between classes.
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An immutable class has no mutator methods.
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A side effect of a method is any externally observable data modification.
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7. |
You should minimize side effects that go beyond modification of the implicit parameter.
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8. |
In Java, a method can never change parameters of primitive type.
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9. |
In Java, a method can change the state of an object reference parameter, but it cannot replace the object reference with another.
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A precondition is a requirement that the caller of a method must meet. If a method is called in violation of a precondition, the method is not responsible for computing the correct result.
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An assertion is a logical condition in a program that you believe to be true.
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If a method has been called in accordance with its preconditions, then it must ensure that its postconditions are valid.
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A static method is not invoked on an object.
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A static field belongs to the class, not to any object of the class.
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The scope of a variable is the region of a program in which the variable can be accessed.
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The scope of a local variable cannot contain the definition of another variable with the same name.
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A qualified name is prefixed by its class name or by an object reference, such as Math.sqrt or other.balance.
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18. |
An unqualified instance field or method name refers to the this parameter.
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19. |
A local variable can shadow a field with the same name. You can access the shadowed field name by qualifying it with the this reference.
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20. |
A package is a set of related classes.
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21. |
The import directive lets you refer to a class of a package by its class name, without the package prefix.
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22. |
Use a domain name in reverse to construct unambiguous package names.
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23. |
The path of a class file must match its package name.
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24. |
Unit test frameworks simplify the task of writing classes that contain many test cases.
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25. |
The JUnit philosophy is to run all tests whenever you change your code.
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