Oracle 1Z0-805 Online Practice Questions and Exam Preparation

Oracle 1Z0-805 Online Questions & Answers

• Question 11:

  Given the code fragment:

  public class Test {

  public static void main (String [] args) {

  Path path1 = Paths.get("D:\\sys\\asm\\.\\data\\..\\..\\mfg\\production.log");

  System.out.println(path1.normalize());

  System.out.println(path1.getNameCount());

  }

  }

  What is the result?

  A. D:\sys\mfg\production.log
  B. D:\\sys\\asm\\.\\data\\. . \\mfg\\production.log
  C. D: \\sys\\asm\\.\\data\\. . \\mfg\\production.log
  D. D: \sys\mfg\production.log
  E. D: \\ sys\\asm\\data\\mfg\\production.log
  A. D:\sys\mfg\production.log

  ---

  The normalize method removes any redundant elements, which includes any "." or "directory/.." occurrences. ThegetNameCount method returns the number of elements in the path.Here there are 8 elements (in the redundant path).

  Reference: The Java Tutorials,Path Operations

• Question 12:

  Given the incomplete pseudo-code for a fork/join framework applications:

  submit (Data) {

  if (Data.size < SMALL_ENOUGH) {

  (Data); // line X

  }

  else {

  List x = (Data); // line Y

  for(Data d: x

  (d); // line Z

  }

  }

  And give the missing methods:

  Process, submit, and splitInHalf

  Which three insertions properly complete the pseudo-code?

  A. Insert submit at line X
  B. Insert splitHalf at line X
  C. Insert process at line X
  D. Insert process at line Y
  E. Insert splitHalf at line Y
  F. Insert process at line Z
  G. Insert submit at line Z
  C. Insert process at line X
  E. Insert splitHalf at line Y
  G. Insert submit at line Z

  ---

  C: If Data.Size is "small enough" then process it directly.

  E: Else we split it in half.

  G: We use a recursive submit (of the splitted Data).

• Question 13:

  The default file system includes a logFiles directory that contains the following files: log ?Jan2009 log_01_2010 log_Feb2010 log_Feb2011 log-sum-2012

  How many files the matcher in this fragment match?

  PathMatcher matcher = FileSystems.getDefault ().getPathMatcher ("glob:???_*1");

  A. One
  B. Two
  C. Three
  D. Four
  E. Five
  F. Six
  A. One

  ---

  The glob pattern is: any three characters, followed by _ ,followed by any number of characters, and ending with a 1.

  Only log_Feb2011 matches this pattern.

  Note:

  You can use glob syntax to specify pattern-matching behavior.

  A glob pattern is specified as a string and is matched against other strings, such as directory or file names. Glob syntax follows several simple rules:

  *

  An asterisk, *, matches any number of characters (including none). ** Two asterisks, **, works like * but crosses directory boundaries. This syntax is generally used for matching complete paths.

  *

  A question mark, ?, matches exactly one character.

  *

  Braces specify a collection of subpatterns. For example:

  {sun,moon,stars} matches "sun", "moon", or "stars."

  {temp*,tmp*} matches all strings beginning with "temp" or "tmp."

  *

  Square brackets convey a set of single characters or, when the hyphen character (-) is used, a range of characters. For example:

  [aeiou] matches any lowercase vowel.

  [0-9] matches any digit.

  [A-Z] matches any uppercase letter.

  [a-z,A-Z] matches any uppercase or lowercase letter.

  *

  Within the square brackets, *, ?, and \ match themselves.

  *All other characters match themselves.

  *

  To match *, ?, or the other special characters, you can escape them by using the backslash character, \. For example: \\ matches a single backslash, and \? matches the question mark.

  Reference: The Java Tutorials

  Finding Files

  What Is a Glob?

• Question 14:

  Which two code blocks correctly initialize a Locale variable?

  A. Locale loc1 = "UK";
  B. Locale loc2 = Locale.get Instance ( "ru" );
  C. Locale loc3 = Locale.getLocaleFactory("RU");
  D. Locale loc4 = Locale.UK;
  E. Locale loc5 = new Locale("ru", "RU");
  D. Locale loc4 = Locale.UK;
  E. Locale loc5 = new Locale("ru", "RU");

  ---

  Reference: The Java Tutorials,Creating a Locale

• Question 15:

  Which two Capabilities does Java.util.concurcent.BlockingQueue provide to handle operation that cannot be handled immediately?

  A. Automatically retry access to the queue with a given periodicity.
  B. Wait for the queue to contain elements before retrieving an element.
  C. Increase the queue's capacity based on the rate of blocked access attempts.
  D. Wait for space to become available in the queue before inserting an element.
  B. Wait for the queue to contain elements before retrieving an element.
  D. Wait for space to become available in the queue before inserting an element.

  ---

  A blocking queue is a Queue that additionally supports operations that wait for the queue to become non-empty when retrieving an element, and wait for space to become available in the queue when storing an element.

  Note: The BlockingQueue interface in the java.util.concurrent class represents a queue which is thread safe to put into, and take instances from.

  The producing thread will keep producing new objects and insert them into the queue, until the queue reaches some upper bound on what it can contain. It's limit, in other words. If the blocking queue reaches its upper limit, the producing

  thread is blocked while trying to insert the new object. It remains blocked until a consuming thread takes an object out of the queue.

  The consuming thread keeps taking objects out of the blocking queue, and processes them. If the consuming thread tries to take an object out of an empty queue, the consuming thread is blocked until a producing thread puts an object into the queue. Reference: Java.util.concurcent.BlockingQueue

• Question 16:

  Which code fragments print 1?

  A. String arr [] = {"1", "2", "3"}; List
  B. String arr [] = {"1", "2", "3"}; List arrList = new LinkedList (Arrays.asList (arr)); System.out.println (arrList.get (0));
  C. String arr [] = {"1", "2", "3"}; List arrList = new LinkedList (Arrays.asList (arr)); System.out.println (arrList.get (0));
  D. String arr [] = {"1","2","3"}; List arrList = new LinkedList (Arrays.asList (arr)); System.out.println (arrList.get (0));
  E. String arr [] = {"1","2","3"}; List extendsString > arrList =new LinkedList (Arrays.asList (arr)); System.out.println (arrList.get (0));
  A. String arr [] = {"1", "2", "3"}; List
  C. String arr [] = {"1", "2", "3"}; List arrList = new LinkedList (Arrays.asList (arr)); System.out.println (arrList.get (0));

  ---

  Note:You can replace the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (<>) as long as the compiler can infer the type arguments from the context. This pair of angle brackets is informally called the diamond.

• Question 17:

  Consider the following database table:

  Inventory Table

  *

  Item_ID, Integer: PK

  *

  Item_name, Varchar (20)

  *

  Price, Numeric (10, 2)

  *

  Quan, Integer

  Consider the following method that updates the prices in the Inventory table:

  public static void updatePrices{

  // #1: missing line

  Connection con) throws SQLException {

  // #2: missing line

  PreparedStatement updatePrices = con.prepareStatement (updatePricesString);

  // #3: missing line

  {

  // #4: missing line

  updatePrices.executeUpdate(); }

  }

  This method us missing four lines, which group of lines complete this method?

  A. 1. HashMap newPrices, 2. StringupdatePriceString ="UPDATE inventory SET price =? WHERE item_name'?'"; 3. For (map.Entry x : newPrices.entrySet()) 4. UpdatePrices.setFloat(1, x.getvalue().floatValue()); updatePrice.setString (2, x.getKey());
  B. 1. HashMap newPrices, 2. StringupdatePriceString ="UPDATE inventory SET price =? WHERE item_id '?'"; 3. For (map.Entry x : newPrices.entrySet()) 4. UpdatePrices.setFloat(1, x.getvalue().floatValue()); updatePrice.setString (2,
  C. getKey().intValue());
  D. 1. HashMap newPrices, 2. StringupdatePriceString = "UPDATE inventory SET price =? Where item_id `?' "; 3. For (map.Entry x : newPrices.entrySet()) 4. UpdatePrices.setInt(1, x.getvalue().floatValue()); updatePrice.setString (2, x.getvalue());
  E. 1. HashMap newPrices, 2. StringupdatePriceString = "UPDATE inventory SET price =? Where item_id `?' "; 3. For (map.Entry x : newPrices.entrySet()) 4. UpdatePrices.setInt(1, x.getvalue().floatValue()); updatePrice.setString (2,
  F. getvalue().floatValue()
  G. 1. HashMap newPrices, 2. StringupdatePriceString = "UPDATE inventory SET price =? Where item_id `?' "; 3. For (map.Entry x : newPrices.entrySet()) 4. UpdatePrices,setString(1, x.getKey()); updatePrices.setFloat(2, x.getValue().floatValue());
  H. 1. HashMap newPrices, 2. StringupdatePriceString = "UPDATE inventory SET price =? Where item_id `?' "; 3. For (Integer x: newPrice) 4. updatePrice.setInt(1, x);
  D. 1. HashMap newPrices, 2. StringupdatePriceString = "UPDATE inventory SET price =? Where item_id `?' "; 3. For (map.Entry x : newPrices.entrySet()) 4. UpdatePrices.setInt(1, x.getvalue().floatValue()); updatePrice.setString (2, x.getvalue());

  ---

  The first line should be HashMap newPrices, as in SQL numeric represent a float number, not an integeror string. We also make sure to use floatValue() both in appropriate places in line 4.

  Note: Map is an object that maps keys to values. A map cannot contain duplicate keys: Each key can map to at most one value. It models the mathematical function abstraction.

• Question 18:

  Given the following code fragment:

  public class Calc {

  public static void main (String [] args) {

  //* insert code here Line **

  System.out.print("The decimal value is" + var);

  }

  }

  Which three code fragments, when inserted independently at line **, enable the code to compile/

  A. int var = 0b_1001;
  B. long var = 0b100_01L;
  C. float var = 0b10_01; D. float var = 0b10_01F; E. double var = 0b10_01;
  D. double var = 0b10_01D;
  B. long var = 0b100_01L;
  C. float var = 0b10_01; D. float var = 0b10_01F; E. double var = 0b10_01;

  ---

  B: output 17

  C: output 9.0

  E: output 9.0

  Not A: A _ character cannot begin a number.

  Not D: A float cannot be defined as a binary number (with literal B) Not F: A float cannot be defined as a decimal number (with literal D)

  Note1:

  In Java SE 7 and later, any number of underscore characters (_) can appear anywhere between digits in a numerical literal. This feature enables you, for example. to separate groups of digits in numeric literals, which can improve the

  readability of your code.

  For instance, if your code contains numbers with many digits, you can use an underscore character to separate digits in groups of three, similar to how you would use a punctuation mark like a comma, or a space, as a separator.

  You can place underscores only between digits; you cannot place underscores in the following places:

  *

  At the beginning or end of a number (not A)

  *

  Adjacent to a decimal point in a floating point literal

  *

  Prior to an F or L suffix

  *

  In positions where a string of digits is expected

  Note 2:An integer literal is of type long if it ends with the letter L or l; otherwise it is of type int. It is recommended that you use the upper case letter L because the lower case letter l is hard to distinguish from the digit 1.

  Values of the integral types byte, short, int, and long can be created from int literals. Values of type long that exceed the range of int can be created from long literals. Integer literals can be expressed by these number systems:

  Decimal: Base 10, whose digits consists of the numbers 0 through 9; this is the number system you use every day

  Hexadecimal: Base 16, whose digits consist of the numbers 0 through 9 and the letters A through F Binary: Base 2, whose digits consists of the numbers 0 and 1 (you can create binary literals in Java SE 7 and later) Reference: The Java Tutorials,Primitive Data Types: Using Underscore Characters in Numeric Literals Integer Literals

• Question 19:

  View the Exhibit:

  

  Given the following code fragment:

  class Finder extends SimpleFileVisitor {

  private final PathMatcher matcher;

  private static int numMatches = 0;

  Finder() {

  matcher = FileSystems.getDefault().getPathMatcher("glob:*java");

  }

  void find(Path file) {

  Path Name = file.getFileName();

  if (name != null andand matcher.matches(name)) {

  numMatches++;

  }

  }

  void report()

  {

  System.out.println("Matched: " + numMatches);

  }

  @Override

  public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) {

  find(file);

  return CONTINUE;

  }

  }

  public class Visitor {

  public static void main(String[] args) throws IOException

  { Finder finder = new Finder();

  Files.walkFileTree(Paths.get("d:\\Project"), finder);

  finder.report();

  }

  }

  What is the result?

  A. Compilation fails
  B. 6
  C. 4
  D. 1
  E. 3
  B. 6

  ---

  The program will compile and run.

  Referring to the exhibit there will be six nodes that matches glob:*java.

• Question 20:

  Which two statements are true about the walkFileTree method of the files class?

  A. The file tree traversal is breadth-first with the given FileVisitor invoked for each file encountered.
  B. If the file is a directory, and if that directory could not be opened, the postVisitFileFailed method is invoked with the I/O exception.
  C. The maxDepth parameter's value is the maximum number of directories to visit.
  D. By default, symbolic links are not automatically followed by the method.
  C. The maxDepth parameter's value is the maximum number of directories to visit.
  D. By default, symbolic links are not automatically followed by the method.

  ---

  C: The method walkFileTree(Path start, Set options, int maxDepth, FileVisitor visitor)

  walks a file tree.

  The maxDepth parameter is the maximum number of levels of directories to visit. A value of 0 means that only the starting file is visited, unless denied by the security manager. A value of MAX_VALUE may be used to indicate that all levels

  should be visited. The visitFile method is invoked for all files, including directories, encountered at maxDepth, unless the basic file attributes cannot be read, in which case the visitFileFailed method is invoked.

  D:You need to decide whether you want symbolic links to be followed. If you are deleting files, for example, following symbolic links might not be advisable. If you are copying a file tree, you might want to allow it. By default, walkFileTree does not follow symbolic links.

  Reference: The Java Tutorials, Walking the File Tree

  Reference: walkFileTree