Java MCQs on String comparision in Java Programming Language.
1. Which of these method of class String is used to compare two String objects for their equality? Answer: a 2. Which of these methods is used to compare a specific region inside a string with another specific region in another string? Answer: d 3. Which of these methods of class String is used to check whether a given object starts with a particular string literal? Answer: a 4. What is the value returned by function compareTo() if the invoking string is less than the string compared? Answer: b 5. Which of these data type value is returned by equals() method of String class? Answer: c 6. What will be the output of the following Java code? a) true 7. What will be the output of the following Java code? a) true true 8. What will be the output of the following Java code? a) true true 9. In the following Java code, which code fragment should be inserted at line 3 so that the output will be: “123abc 123abc”? a) sb1.append(“abc”); s1.append(“abc”); Answer: d 10. What will be the output of the following Java code? a) ab
a) equals()
b) Equals()
c) isequal()
d) Isequal()
Clarification: None.
a) regionMatch()
b) match()
c) RegionMatches()
d) regionMatches()
Clarification: None.
a) startsWith()
b) endsWith()
c) Starts()
d) ends()
Clarification: Method startsWith() of string class is used to check whether the String in question starts with a specified string. It is a specialized form of method regionMatches().
a) zero
b) value less than zero
c) value greater than zero
d) none of the mentioned
Clarification: compareTo() function returns zero when both the strings are equal, it returns a value less than zero if the invoking string is less than the other string being compared and value greater than zero when invoking string is greater than the string compared to.
a) char
b) int
c) boolean
d) all of the mentioned
Clarification: equals() method of string class returns boolean value true if both the string are equal and false if they are unequal.
class output
{
public static void main(String args[])
{
String c = "Hello i love java";
boolean var;
var = c.startsWith("hello");
System.out.println(var);
}
}
b) false
c) 0
d) 1
Clarification: startsWith() method is case sensitive “hello” and “Hello” are treated differently, hence false is stored in var.
Output:
$ javac output.java
$ java output
false
class output
{
public static void main(String args[])
{
String s1 = "Hello i love java";
String s2 = new String(s1);
System.out.println((s1 == s2) + " " + s1.equals(s2));
}
}
b) false false
c) true false
d) false true
Clarification: The == operator compares two object references to see whether they refer to the same instance, where as equals() compares the content of the two objects.
Output:
$ javac output.java
$ java output
false true
class output
{
public static void main(String args[])
{
String s1 = "Hello";
String s2 = new String(s1);
String s3 = "HELLO";
System.out.println(s1.equals(s2) + " " + s2.equals(s3));
}
}
b) false false
c) true false
d) false true
Clarification: None.
Output:
$ javac output.java
$ java output
true false
1. StringBuilder sb1 = new StringBuilder("123");
2. String s1 = "123";
3. // insert code here
4. System.out.println(sb1 + " " + s1);
b) sb1.append(“abc”); s1.concat(“abc”);
c) sb1.concat(“abc”); s1.append(“abc”);
d) sb1.append(“abc”); s1 = s1.concat(“abc”);
Clarification: append() is stringbuffer method and concat is String class method.
append() is stringbuffer method and concat is String class method.
class output
{
public static void main(String args[])
{
String chars[] = {"a", "b", "c", "a", "c"};
for (int i = 0; i < chars.length; ++i)
for (int j = i + 1; j < chars.length; ++j)
if(chars[i].compareTo(chars[j]) == 0)
System.out.print(chars[j]);
}
}
b) bc
c) ca
d) ac
Clarification: compareTo() function returns zero when both the strings are equal, it returns a value less than zero if the invoking string is less than the other string being compared and value greater than zero when invoking string is greater than the string compared to.
output:
$ javac output.java
$ java output
ac