5 points QUESTION 21 The three major categories of Java collections are tree set

Question

5 points   

QUESTION 21

The three major categories of Java collections are

tree sets, list sets, and hash maps

lists, sets, and maps

hash lists, hash tables, and sets

sets, collections, and maps

5 points   

QUESTION 22

Given that String[] str has been initialized, to get a copy of str[0] with all characters converted to upper case, use the following statement

str.uppercase();

str[0].toUpperCase();

str.toUpperCase();

str[0].upperCase();

5 points   

QUESTION 23

What would be the results of the following code?

final int SIZE = 25;
int[] array1 = new int[SIZE];

... // Code that will put values in array1

int value = 0;
for (int a = 0; a <= array1.length; a++)
{
value += array1[a];
}

value contains the lowest value in array1

value contains the sum of all the values in array1

value contains the highest value in array1

This would cause the program to crash.

5 points   

QUESTION 24

What is the value of str after the following code has been executed?

String str;
String sourceStr = "Hey diddle, diddle, the cat and the fiddle";
str = sourceStr.substring(12,17);

Iddle

diddl

diddle

, didd

5 points   

QUESTION 25

If a subclass constructor does not explicitly call a superclass constructor,

The superclass fields will be set to the default values for their data types

It must include the code necessary to initialize the superclass fields

Java will automatically call the superclass's default constructor just before the code in the subclass's constructor executes

Java will automatically call the superclass's default constructor immediately after the code in the subclass's constructor executes

5 points   

QUESTION 26

What term refers to data that describes other data?

meta data

pseudo-data

micro data

abstract data

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QUESTION 27

If a class contains an abstract method,

The method must be overridden in subclasses

You cannot create an instance of the class

The method will have only a header, but not a body, and end with a semicolon

All of the above

5 points   

QUESTION 28

In the following code, System.out.println(num), is an example of ________.

double num = 5.4;

System.out.println(num);

num = 0.0;

A value-returning method          

A local variable

A complex method      

A void method

5 points   

QUESTION 29

In the realm of JDBC use of PreparedStatements help prevent what?

SQL Injection

increased threads

does not prevent anything, just executes insert statements like JDBC statements do

execution of stored procedures

5 points   

QUESTION 30

If a subclass constructor does not explicitly call a superclass constructor,

It must include the code necessary to initialize the superclass fields

The superclass fields will be set to the default values for their data types

Java will automatically call the superclass's default constructor just before the code in the subclass's constructor executes

Java will automatically call the superclass's default constructor immediately after the code in the subclass's constructor executes

tree sets, list sets, and hash maps

lists, sets, and maps

hash lists, hash tables, and sets

sets, collections, and maps

Explanation / Answer

21) lists, sets, and maps

three main kind of collections are: - OrderedCollections or lists, Collections or sets and maps.

22) str[0].toUpperCase();

   Str is an array and array has no toUpperCase() function but element of String array have this function.

23) value contains the sum of all the values in array1

       Value is initialized with 0 then in each iteration of for loop, element of array is added to the value. So it contains the sum.

24) diddl

As it returns substring starting from position from 12 till before 17

25) Java will automatically call the superclass's default constructor just before the code in the subclass's constructor executes

This is because the first line in constructor should be call of super() constructor. If it is not there, a call to default one of super class will be added. If default constructor of super is not present, it will throw compilation error.

26) meta data

Metadata contains the data/information about the other data.

27) All of the above

This is the property of abstract class, that they cannot be instantiated, there abstracts needs to be defined in subclass and abstract method must not be defined in abstract class.

28) A void method

It is not returning anything else. Just saving a value in num.

29) SQL Injection

It prevents from SQL injection because all the parameters passed will be escaped by JDBC driver.

30) Java will automatically call the superclass's default constructor just before the code in the subclass's constructor executes

As explained in Q. 25.

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