Question

if x ant y are both arrays of int values which of the following shows a call to a method of the arrays class that will determine if the two arrays have the same contents?
a. boolean b = java.util.Arrays.compare(x, y);
b. boolean b = java.util.Arrays.equals(x, y);
c. boolean b = java.util.Arrays.check(x, y);
d. boolean b = java.util.Arrays.binaryCompare (x, y);

Answer 1

b. boolean b = java.util.Arrays.equals(x, y);  
This problem is simply a matter of knowing the java library classes, or knowing how to look up the library classes and reading the documentation for the the class methods within the libraries. So let's look at the options and find the correct one. 
 a. boolean b = java.util.Arrays.compare(x, y); 
 * There is no class method "compare" under java.util.Arrays, so this option is wrong. 
 b. boolean b = java.util.Arrays.equals(x, y);
 * This is the correct answer. "equals" is a heavily overloaded class method, one of the overloaded definitions receiving two integer arrays and returning equal if the contents of the arrays are equal to each other. 
 c. boolean b = java.util.Arrays.check(x, y); 
 * There is no class method "check" under java.util.Arrays, so this option is wrong. 
 d. boolean b = java.util.Arrays.binaryCompare (x, y);
 * There is no class method "binaryCompare" under java.util.Arrays, so this option is wrong.