Oracle 1z0-809 問題集

質問 1：
Which two are elements of a singleton class? (Choose two.)
A. a private constructor to the class
B. a transient reference to point to the single instance
C. a public reference to point to the single instance
D. a public static method to return a copy of the singleton reference
E. a public method to instantiate the single instance
正解：A,E

質問 2：
Assume customers.txt is accessible and contains multiple lines.
Which code fragment prints the contents of the customers.txt file?
A. Stream<Path> stream = Files.find (Paths.get ("customers.txt"));stream.forEach( c) -> System.out.println(c));
B. Stream<Path> stream = Files.list (Paths.get ("customers.txt"));stream.forEach( c) -> System.out.println(c));
C. Stream<String> lines = Files.lines (Paths.get ("customers.txt"));lines.forEach( c) -> System.out.println(c));
D. Stream<String> stream = Files.find (Paths.get ("customers.txt"));stream.forEach((String c) -> System.out.println(c));
正解：C

質問 3：
Given the code fragments:

and

What is the result?
A. class java.lang.Exception
B. Video played.Game played.
C. class java.io.IOException
D. A compilation error occurs.
正解：A

質問 4：

What is the result?
A. A compilation error occurs at line 7.
B. A compilation error occurs at line 8.
C. A compilation error occurs at line 15.
D. 100
正解：A

質問 5：
Given the records from the STUDENT table:

Given the code fragment:

Assume that the URL, username, and password are valid.
What is the result?
A. The STUDENT table is not updated and the program prints:114 : John : [email protected]
B. The STUDENT table is updated with the record:113 : Jannet : [email protected] the program prints:114 : John : [email protected]
C. The STUDENT table is updated with the record:113 : Jannet : [email protected] the program prints:113 : Jannet : [email protected]
D. A SQLException is thrown at run time.
正解：D

質問 6：
Given the code fragment:
List<String> str = Arrays.asList ("my", "pen", "is", "your', "pen");
Predicate<String> test = s -> {
int i = 0;
boolean result = s.contains ("pen");
System.out.print(i++) + ":");
return result;
};
str.stream()
.filter(test)
.findFirst()
.ifPresent(System.out ::print);
What is the result?
A. 0 : 0 : 0 : 0 : 0 : pen
B. 0 : 0 : pen
C. A compilation error occurs.
D. 0 : 1 : pen
E. 0 : 1 : 2 : 3 : 4 :
正解：B

質問 7：
Given the code fragment:

Which should be inserted into line n1 to print Average = 2.5?
A. IntStream str = IntStream.of (1, 2, 3, 4);
B. IntStream str = Stream.of (1, 2, 3, 4);
C. Stream str = Stream.of (1, 2, 3, 4);
D. DoubleStream str = Stream.of (1.0, 2.0, 3.0, 4.0);
正解：D

質問 8：
Given the code fragment:

Which two code fragments, when inserted at line n1 independently, result in the output PEEK: Unix?
A. .findAny ();
B. .allMatch ();
C. .noneMatch ();
D. .anyMatch ();
E. .findFirst ();
正解：A,E

質問 9：
Given the code fragment:

and the information:
* The required database driver is configured in the classpath.
* The appropriate database is accessible with the dbURL, username, and passWord exists.
What is the result?
A. The program prints nothing.
B. The program prints Connection Established.
C. A SQLException is thrown at runtime.
D. A ClassNotFoundException is thrown at runtime.
正解：B