1Z0-804

Question 1

Which three access modifiers are allowed for class and instance members?

Answer 1

public, private, protected

Question 2

Which element will be retrieved from the path C:\paul\baker\java7\804.java when executing the method getName(3)?

Answer 2

804.java

Question 3

In a format string, what does the % character specify?

Answer 3

beginning of a format parameter

Question 4

In a glob pattern, what do the curly braces {} contain?

Answer 4

subpatterns that are comma delimited

Question 5

In a String, which character is required to escape the initial backslash for Java?

Answer 5

\

Question 6

Which method of the Object class determines the bucket in which an object is placed in a Hashtable?

Answer 6

hashCode, hashCode returns an int value.

Question 7

What is the local connection string syntax for the Java DB Network Client Driver?

Answer 7

jdbc:derby://localhost:port/databaseName

Question 8

Which superclass constructor is implicitly invoked by the compiler in a subclass that does not explicitly invoke a specific superclass constructor?

Answer 8

The constructor with no parameters.

Question 9

Which two fields are the default values for a ResultSet object?

Answer 9

CONCUR_READ_ONLY and TYPE_FORWARD_ONLY

Question 10

Using SimpleDateFormat class, what does the pattern letter a represent?

Answer 10

AM/PM marker

Question 11

In a format string, what does the $ character specify?

Answer 11

The end of an argument location.

String.format(“%1$s %2$s %2$s %3$s”, “a”, “b”, “c”);

Question 12

Which keyword provides only visibility when using shared variables across multiple threads?

Answer 12

volatile

Question 13

Which BasicFileAttributeView subinterface supports allowing or disallowing permissions on file system objects for a specified identity other than the owner?

Answer 13

AclFileAttributeView

Question 14

What is the thread-safe version of the Queue class found in the java.util.concurrent package?

Answer 14

BlockingQueue

Question 15

What are the patterns supported by Glob Syntax?

Answer 15

<code>
* - matches any string of any length, even 0 length
** - similar to * but crosses dir boundaries
? - matches any single character
[xyz] - matches letters x,y or z
[0-5] - match range
{xyz, abc}  - matches either xyz or abc
</code>

Question 16

What are the Concurrent Collections?

Answer 16

BlockingQueue (I), ArrayBlockingQueue (C),
LinkedBlockingQueue (C), DelayQueue,
PriorityBlockingQueue, SynchronousQueue,
LinkedBlockingDeque, ConcurrentHashMap,
ConcurrentSkipListMap, ConcurrentSkipListSet,
CopyOnWriteArrayList, CopyOnWriteArraySet

Question 17

This concurrent collection interface extends the Queue interface. If the queue is empty, it waits for an element to be inserted, and if the queue is full, it waits for an element to be removed from the queue. What is the name of this interface?

Answer 17

BlockingQueue

Question 18

What classes implement the concurrent collection BlockingQueue interface?

Answer 18

ArrayBlockingQueue, 
LinkedBlockingQueue, 
DelayQueue
PriorityBlockingQueue
SynchronousQueue

Question 19

This class provides a fixed-size array based implementation of the BlockingQueue interface. What is the name of this concurrent collection class?

Answer 19

ArrayBlockingQueue

Question 20

This class provides a linked list based implementation of the BlockingQueue interface. What is the name of this concurrent collection class?

Answer 20

LinkedBlockingQueue

Question 21

This class implements BlockingQueue and consists of elements that are of type Delayed. An element can only be retrieved from this queue only after its delay period. What is the name of this concurrent collection class?

Answer 21

DelayQueue

Question 22

Equivalent to java.util.PriorityQueue, but implements that BlockingQueue interface. What is the name of this concurrent collection class?

Answer 22

PriorityBlockingQueue

Question 23

This class implements BlockingQueue. In this container, each insert() by a thread waits for a corresponding remove() by another thread. What is the name of this concurrent collection class?

Answer 23

SynchronousQueue

Question 24

This class implements BlockingDeque where insert and remove operations could block; uses a linked-list for implementation. What is the name of this concurrent collection class?

Answer 24

LinkedBlockingQueue

Question 25

Analogous to HashTable, but with safe concurrent access and updates. What is the name of this concurrent collection class?

Answer 25

ConcurrentHashMap

Question 26

Analogous to TreeMap, but with safe concurrent access and updates. What is the name of this concurrent collection class?

Answer 26

ConcurrentSkipListMap

Question 27

Analogous to TreeSet, but with safe concurrent access and updates. What is the name of this concurrent collection class?

Answer 27

ConcurrentSkipListSet

Question 28

Similar to ArrayList, but provides safe concurrent access. When the ArrayList is update, it creates a fresh copy of the underlying array. What is the name of this concurrent collection class?

Answer 28

CopyOnWriteArrayList

Question 29

A Set implementation, but provides safe concurrent access and is implemented using CopyOnWriteArrayList. When the container is updated, it creates a fresh copy of the underlying array. What is the name of this concurrent collection class?

Answer 29

CopyOnWriteArraySet

Question 30

Which BasicFileAttributeView subinterface supports the attributes group and permissions?

Answer 30

PosixFileAttributeView

Question 31

In class inheritance, which term describes the unique implementation of a superclass method in a subclass?

Answer 31

polymorphism

Question 32

Which Console method ensures secure entry by suppressing the echo of characters and returning a char array that can be overwritten?

Answer 32

readPassword

Question 33

What is another term for request-forwarding in a composition relationship?

Answer 33

method delegation

Question 34

Which isolation level uses a shared locking mechanism that only prevents access to uncommitted values?

Answer 34

TRANSACTION_READ_COMMITTED

Question 35

Which class provides the best performance when generating random numbers in a multi-threaded application?

Answer 35

ThreadLocalRandom

Question 36

Which method of the BufferedReader class ignores and discards a specified number of characters?

Answer 36

skip

Question 37

Which keyword is used to implement abstract members of an abstract class?

Answer 37

extends

Question 38

Which exception is thrown when an assert statement evaluates to false?

Answer 38

AssertionError

Question 39

In a glob pattern, what does the asterisk character match?

Answer 39

Zero or more characters.

Question 40

Which FileVisitResult value, when returned from the preVisitDirectory method, will visit file and directory entries?

Answer 40

CONTINUE

Question 41

Which method does the Enum class provide to iterate through enumeration constants?

Answer 41

values

Question 42

In which pattern is a data-related class is concerned only with storage and read/write access to its instance members?

Answer 42

TransferObject TO

Question 43

Which FileVisitor method is invoked for each file when it is visited?

Answer 43

visitFile

Question 44

Which String method accepts a regular expression and replacement string for each match, and returns a manipulated string?

Answer 44

replaceAll

Question 45

Which type determines the version of a hidden member to use without polymoprhism?

Answer 45

the reference type

Question 46

Using SimpleDateFormat class, what does the pattern letter S represent?

Answer 46

Millisecond

Question 47

What SimpleDataFormat letter is used to represent - Seconds? Milliseconds?

Answer 47

``` s = seconds S = milliseconds ```

Question 48

What does the phrase covariant return types describe?

Answer 48

An overriding method can return a subtype of the return type of the overridden method.