Questions and Answers
In Java, it is possible to write a method that will return ________.
a string of characters, a whole number, and a reference to an object
Java automatically stores a ________ value in all uninitialized static member variables.
0 (zero)
Static methods can only operate on ________ fields.
static
The 'has a' relationship is sometimes called a(n) ________ because one object is part of a greater whole.
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The key word this is the name of a reference variable that an object can use to refer to itself.
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The whole-part relationship created by object aggregation is more often called a(n) ________ relationship.
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To compare two objects in a class, ________.
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When a field is declared static there will be ________.
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When a method's return type is a class, what is actually returned to the calling program?
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When a reference variable is passed as an argument to a method ________.
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When an object is passed as an argument, it is actually a reference to the object that is passed.
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When an object reference is passed to a method, the method may change the values in the object.
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Study Notes
Java Methods and Variables
- A Java method can return various data types including strings, whole numbers, and object references.
- Uninitialized static member variables in Java are automatically assigned a default value of zero.
- Static methods are restricted to operating only on static fields within a class.
Object Relationships
- The "has a" relationship, also known as a whole-part relationship, signifies that one object is a component of another.
- Object aggregation is frequently characterized by this whole-part relationship.
Self-Referencing and Object Comparison
- The keyword
thisserves as a reference variable that allows an object to refer to itself. - To compare two objects, an
equalsmethod should be implemented to perform a field-by-field comparison.
Static Fields and Memory Management
- When a field is declared as static, there is only a single copy stored in memory, regardless of how many instances of the class exist.
- Methods whose return types are classes return references, not the objects themselves, to the calling program.
Passing References to Methods
- When a reference variable is used as a method argument, the method gains access to the actual object referenced by that variable.
- Passing an object as an argument corresponds to passing a reference to that object.
- Methods that receive an object reference can modify the object's internal values.
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Description
Explore key concepts in Java programming, focusing on methods, variables, and object relationships. Understand how static fields operate and the importance of the 'this' keyword in self-referencing objects. This quiz will enhance your knowledge of Java's unique features and memory management techniques.
