Section 1
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Which of the following are interfaces to ArrayList? List, Map, Queue, RandomAccess, and Set.
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Section 1
(50 cards)
Which of the following are interfaces to ArrayList? List, Map, Queue, RandomAccess, and Set.
List and RandomAccess are interfaces to ArrayList.
Will this line compile without errors? Object [ ] obj = new Object ();
Incorrect because they have () instead of [] after the type.
When you pass a variable as an argument to a method call, what are you passing?
A copy of the value. You always get a copy of whatever is in the variable - either a primitive or a reference. So for objects, you get a copy of the reference.
What is the keyword transient?
It marks a member variable not to be serialized when it is persisted to streams of bytes.
Can a constructor be declared static?
No, constructors are for creating new instance objects. Static methods are for non-instance code, so it makes no sense to have a static constructor.
What will be printed? System.out.println("roberto".substring(3, 7));
erto
What access is the generated constructor given when one is not supplied?
If the class is public, than it is public. Otherwise the default constructor is default.
Can a constructor be declared private?
Yes. This can be used to control the creation of the object by other less restrictive methods.
Can a constructor have a synchronized modifier?
No; they can never be synchronized.
Are instance variables assigned a default value?
Yes, member or instance variables are always given a default value.
What will be printed? System.out.println("roberto".replaceAll("o", "!").substring(2, 6));
bert
Can a private method be overridden?
No, but the can be re-declared in the subclass. This is not polymorphism.
Can you compare a boolean to an int?
No, booleans are true and false keywords and nothing else.
What is the keyword native?
The native keyword is applied to a method to indicate that the method is implemented in native code using JNI.
Will this line compile without errors? double[ ][ ][ ] numbers = new double[ ][ ][ ];
No. When the new operator is used, at least one array dimension in a multi-dimensional array must be given a size.
What are the access specifiers in order of most restrictive to least?
Private, Default, Protected, and Public.
What does continue do?
The continue statement skips the current iteration of a for, while, or do-while loop. The unlabeled form skips to the end of the innermost loop's body and evaluates the boolean expression that controls the loop. A labeled continue statement skips the current iteration of an outer loop marked with the given label.
Will this line compile without errors? Object [3] obj = new Object [3]() ;
Incorrect because the size is in the declaration and the extra () after the [] is not the correct syntax.
Will this line compile without errors? Object obj [ ] = new Object [3]();
Incorrect because the () after the [] is not the correct syntax.
Will this line compile without errors? Object [7] obj = new Object [7];
Incorrect because the size is not assigned when it is declared.
What is the output of the following code segment? int value = 1; switch (value) { case 0: System.out.println("Dog"); case 1: System.out.println("Cat"); case 1: System.out.println("Fish"); default: System.out.println("Cow"); }
This will not compile because it includes a case statement with the same value twice.
Fill in the blank. Import statements are ______.
Required in all versions of Java.
What will be printed? System.out.println("roberto".replaceAll("o","!").substring(1, 6));
!bert
Will this line compile without errors? Object [ ] obj = new Object [ ];
Incorrect because they do not assign a size to the array.
What are the access levels in order of most restrictive to least?
Class, Package, Sub class, and World.
If break statements are not used in a switch, what will happen?
Once a case statement is entered, the code will continue to execute in each case below it, until it hits a break statement.
Will this line compile without errors? Object obj = new Object ();
Yes.
Can the access specifier for an overriding method allow more or less access than the overridden method?
More. The access specifier for an overriding method can allow more, but not less, access than the overridden method.
Will this line compile without errors? Object obj [ ] = new Object [7];
Yes.
Given: public void simpleTest () { int i; System.out.println(i); } What will occur?
A compiler error will occur since the value has not been initialized.
Will this line compile without errors? Object obj [ ] = {new Object [1], new Object [2]};
Yes.
Where can an anonymous inner class be defined?
An anonymous class is an expression. So anywhere an expression is used.
Will this line compile without errors? Object obj [ ] = new Object[ ] ;
Incorrect because they do not assign a size to the array.
Can a top-level class be marked as protected?
No, a top-level class can only be marked public or default. The protected access is just for member variables and methods, and allows subclasses outside the superclass package to inherit the protected members.
Will this line compile without errors? Object obj [] = new {new Object(), new Object()};
Incorrect because the first new operator is being used with the {} initialization method.
Will this line compile without errors? Object [ ] obj = new Object [3]();
Incorrect because the () after the [] is not the correct syntax.
Will this line compile without errors? Object [ ] obj = new Object [7];
Yes.
True or False - during arithmetic, when the operands or different types, the resulting type is always the widest of the two type.
False, the result of an arithmetic operation on any two primitive operands will be at least an int -- even if the operands are byte and short.
Can a class be declared as final?
Yes, a class can be declared final; that is, the class cannot be sub-classed. This is done for security and design.
What best describes the result of the following code segment? The ArrayList sampleArrayList has already been declared and initialized. int i = 63; sampleArrayList.add(i);
The int is converted to an Integer via auto boxing and then placed into the ArrayList. Primitives cannot be stored in an ArrayList. However, if they are placed into their primitive wrapper class they can be stored. Java will automatically make that conversion via its autoboxing feature if a primitive is placed into an ArrayList.
What is the difference between the default and protected access specifier?
Default does not allow sub class access. Both allow package access.
Will this line compile without errors? Object obj [ ] = {new Object(), new Object()};
Yes.
Will this line compile without errors? double[ ][ ][ ] numbers = new double[7][ ][ ];
Yes.
Does each source file need a public class in it?
No.
What does break do?
The break statement has two forms: labeled and unlabeled. An unlabeled break statement terminates the innermost switch, for, while, or do-while statement, but a labeled break terminates an outer statement.
What will be printed? System.out.println("roberto".replaceAll("o", "!").substring(1, 7));
!bert!
Will this line compile without errors? Object obj [ ] = new Object() ;
Incorrect because they have () instead of [] after the type.
Can overriding methods throw different exceptions than that of the super?
Overriding methods cannot throw any new or broader exception that is checked. Unchecked does not apply.
Will this line compile without errors? double[ ][ ] numbers = {{1,2,3},{7,8},{4,5,6,9}};
Yes.
Will this line compile without errors? Object [8] obj = new Object [ ];
Incorrect because the size is not assigned when it is declared.
Section 2
(32 cards)