Scjp Chapter 1 Declarations And Access Control

Front 1

Identifiers MUST start with what characters?

Back 1

a letter
a currency character ($, euro, yen etc)
a connecting character (e.g. _)

Front 2

Can an identifier start with a number?

Back 2

No

Front 3

What characters are valid in an identifier after the first character

Back 3

no limitation
any combination of letters, numbers, currency characters or connecting characters

Front 4

Is there a limit to the number of characters an identifier can contain?

Back 4

No

Front 5

what is the format of an octal literal?

Back 5

A string of digits between 0 and 7, beginning with the digit 0

Front 6

How many access modifiers are there, and what are their names?

Back 6

public
protected
default (package)
private

Front 7

What is the difference between protected access and default/package access?

Back 7

Protected access allows (inheritence) access for member or methods to subclasses in ANY package
Default/Package access ONLY allows access (reference or inheritence) to classes or subclasses in the same package

Front 8

Which of the following declarations are legal?

a) void doStuff(int x...){}
b) void doStuff(char...y, int x){}
c) void doStuff(int x, char... c){}
d) void doStuff(int x, float ...f){}
e) void doStuff(int...i, String...s){}

Back 8

c) void doStuff(int x, char...c){}

The rules for var-arg declarations are:
1. The syntax for a var-arg declaration is type... varName (i.e. a valid type followed immediately by an ellipsis [...] followed by a variable name)
2. Only 1 var-arg parameter is permitted in a method signature
3. If a signature includes a var-arg it MUST be the last parameter in the signature

Front 9

Which of the following modifiers are permitted on a constructor declaration?

public
protected
private
static
abstract
strictfp
synchronized
native
final

Back 9

access modifiers (public, protected ..)
strictfp
synchronized
native

Front 10

Is it legal to declare a constructor in an abstract class?

Back 10

yes (check), but it isn't legal to call a constructor in an abstract class (an abstract class cannot be instantiated)
The constructor could only be called for a concrete class which extended the abstract class and provided implementations for any abstract methods

Front 11

Is it possible to call a concrete method in an abstract class?

Back 11

yes (as long as the method is static and called as a class method)

Front 12

Where can an enum be defined?

Back 12

1) Outside of all classes (in a class file with other classes)
2) As a class member (within a class, but outside of all methods)

Note: An enum cannot be defined within a method

Front 13

What access modifiers are permitted with an enum definition?

Back 13

public or default/package

Front 14

What implicit modifiers are associated with ALL Interface constants?

Back 14

public static final

Front 15

Is it legal to define a class as abstract if it contains no abstract methods?

Back 15

Yes

Front 16

What modifiers are associated with all interface methods regardless of their signature?

Back 16

public abstract