单项选择题X 纠错
A. add this code after line 11: list = (List
B. change lines 12 and 13 to: list.add
C. change the method signature on line 11 to: public void addStrings(List< extends String> list) {
D. change the method signature on line 11 to: public void addStrings(List< super String> list) {
E. No changes are necessary. This method compiles without warnings.
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单项选择题
A. 42
B. 0042
C. An exception is thrown at runtime.
D. Compilation fails because of an error in line 13.
E. Compilation fails because of an error in line 14.
多项选择题
A. String s = strings.get(0);
B. Iterator i1 = strings.iterator();
C. String[] array1 = strings.toArray();
D. Iterator
E. String[] array2 = strings.toArray(new String[1]);
F. Iterator
单项选择题
A. 4:4:2:2
B. 4:4:3:2
C. 2:2:1:0
D. 2:2:0:0
E. 2:1:0:0
F. 2:2:1:1
G. 4:3:2:1
多项选择题
A. The hashCode method for a given class can be used to test for object equality and object inequality for that class.
B. The hashCode method is used by the java.util.SortedSet collection class to order theelements within that set.
C. The hashCode method for a given class can be used to test for object inequality, but NOT object equality, for that class.
D. The only important characteristic of the values returned by a hashCode method is that the distribution of values must follow a Gaussian distribution.
E. The hashCode method is used by the java.util.HashSet collection class to group the elements within that set into hash buckets for swift retrieval.
单项选择题
A. The equals method does NOT properly override the Object.equals method.
B. Compilation fails because the private attribute p.name cannot be accessed in line 5.
C. To work correctly with hash-based data structures, this class must also implement the hashCode method.
D. When adding Person objects to a java.util.Set collection, the equals method in line 4 will prevent duplicates.
单项选择题
A. Compilation fails because the hashCode method is not overridden.
B. A HashSet could contain multiple Person objects with the same name.
C. All Person objects will have the same hash code because the hashCode method is not overridden.
D. If a HashSet contains more than one Person object with name=”Fred”, then removing another person, also with name=”Fred”, will remove them all.
多项选择题
A. public int hashCode()
B. public boolean equals(Key k)
C. public int compareTo(Object o)
D. public boolean equals(Object o)
E. public boolean compareTo(Key k)
单项选择题
A. return super.hashCode();
B. return name.hashCode() + age * 7;
C. return name.hashCode() + comment.hashCode() /2;
D. return name.hashCode() + comment.hashCode() / 2 - age * 3;
单项选择题
A. java.util.Queue
B. java.util.ArrayList
C. java.util.LinearList
D. java.util.LinkedList
单项选择题
A. public int compareTo(Object o) {/*mode code here*/}
B. public int compareTo(Score other) {/*more code here*/}
C. public int compare(Score s1,Score s2){/*more code here*/}
D. public int compare(Object o1,Object o2){/*more code here*/}