Operators and Decision Constructs Flashcards
Which types can be used as switch variables?
String, byte, char, short, int, and enum, as well as their respective wrapper classes.
T/F: Case constants must be assignable to the switch variable.
True.
T/F: If the switch variable is of the String type, you can still use int for the case labels
False.
Will this compile:
byte b = 10;
switch(b) {
case 300: //valid code;
}
No.
The case constants cannot be bigger than what the switch variable can store.
Can there be more than one case constant with the same value in a switch statement?
No.
T/F: There can be multiple labels for a a switch statement.
False.
Which operators will not necessarily evaluate all operands?
||
? :
&&
What are the integral types?
byte, short, int, long, and char.
These are primitive types which can holder integer values.
T/F: The modulus operator can only be used on integer operands.
False.
It can also be used on floating point operands.
Is this statement legal:
if (false) ; else ;
Yes.
An if-clause and else-clause can have empty statements.
T/F: An abstract class can be extended by an abstract class or a concrete class
True
T/F: A concrete class can be extended by an abstract or concrete class.
True
T/F: An Interface can be extended by another interface
True
T/F: An interface can be extended by an abstract class.
False.
A class implements an interface, not extend.
T/F: An interface can be extended by a concrete class.
False.
T/F: An abstract class cannot implement an interface.
False.
Any class can implement an interface.
What is the order of access modifiers from most restrictive to least?
private > default (no modifier) > protected > public
From where are private members accessible?
Only from within the class itself.
From where can a member with default access (no modifier) be accessed?
From within the class itself or classes in the same package.
From where can a protected member be accessed?
From within the class itself or from within the same package.
From where can a public member be accessed?
From anywhere.
What is at the root of any inheritance hierarchy?
Object
Which operator takes precedence ` != ` or ` = ` ?
The boolean operator ` != ` takes precedence over the assignment operator ` = `
Which operator takes precedence, the dot operator or the cast operator?
The dot operator takes precedence over the cast operator.
A dot operator (or separator):
objectReference.methodName(argumentList);
A cast operator:
(Integer)
What is the result of the following code?
boolean b1 = false;
boolean b2 = false;
if (b2 = b1 == false){
System.out.println("true");
} else{
System.out.println("false");
}
It prints true.
Remember that every expression has a return value.
