1. What is the return type of remove(Object) method of Collection interface? Choose the right option. 1. boolean 2. Object 3. int 4. Integer 2. What is the output of the following snippet of code? Choose the right option. List numbers1 = new ArrayList(); numbers1.add(2); numbers1.add(1); numbers1.set(1, 2); System.out.println(numbers1); 1. [1, 2] 2. [1, 1] …
1. The method that writes a string of DataOutputStream is 1. writeLine(String) 2. write(String) 3. writeString(String) 4. writeBytes(String) 2. What about the following snippet of code? Choose the right one that is true. Hashtable ht = new Hashtable(); ht.put(“marks”, 40); ht.put(“marks”, 50); System.out.println(ht.get(“marks”)); 1. prints 40 2. prints 50 3. Compilation error 4. Throws exception …
1. null key is not accepted by which data structure? 1. HashMap 2. Hashtable 3. List 4. Set 2. What is the output of the following snippet of code? List myList = new ArrayList(); List yourList = new ArrayList(); myList.add(10); myList.add(20); yourList.add(30); yourList.add(40); myList.addAll(yourList); System.out.println(yourList); 1. [10, 20 ] 2. [30, 40 ] 3. [10, …
1. What is the return type of insertElementAt(Object, int) method of Vector? 1. Object 2. boolean 3. void 4. int 2. Observe the following code snippet and choose the right option. List fruits = new ArrayList(); fruits.add(“mango”); ListIterator li1 = fruits.listIterator(); while(li1.hasNext()) { fruits.add(“apple”); System.out.println(li1.next()); } 1. Compiles and at execution throws ConcurrentModificationException 2. prints …
1. What is the default capacity and increment rate of Vector? 1. 10 and 10 2. 10 and 11 3. 11 and 11 4. 10 and 5 2. What is the return type of add(Object) method of interface Collection? 1. void 2. boolean 3. Object 4. int 3. Choose more appropriate option. currentThread() method of …
1. Which method gives the index position of an element in Stack data structure? 1. indexOf() 2. search() 3. elementAt() 4. elementIndexOf() 2. The removeRange(3, 8) removes all the elements in Vector 1. from 3 to 8 2. from 3 to 7 3. from 2 to 8 4. from 2 to 7 3. What is …
1. What is the index position of element 10 in the Stack? Stack st = new Stack(); st.push(10); st.push(20); st.push(30); 1. 0 2. 1 3. 2 4. 3 2. With what you can fill up the blank so that the output is Hyderabad. List cities = new ArrayList(); cities.add(“Hyderabad”); ——- abc = cities.get(0); System.out.println(abc); 1. …
1. Which interface is not in the Collection hierarchy? 1. List 2. Set 3. Map 4. Queue 2. What is the output of the following snippet of code? Hashtable ht = new Hashtable(); StringBuffer sb1 = new StringBuffer(“hello”); ht.put(sb1, “sir”); Enumeration e = ht.keys(); while(e.hasMoreElements()) { Object obj1 = e.nextElement(); Object obj2 = ht.get(obj1); System.out.println(obj1 …
1. Following snippet of code String citiesArray[] = { “Hyderabad”, “Chennai”, “Vizag”, “Delhi” }; List citiesList = Arrays.asList(citiesArray); for(String temp : citiesList) { System.out.println(temp); } 1. raises compilation error 2. compiles but throws exception 3. compiles, executes and prints all the elements 4. last element is not printed 2. Observe, the following snippet of code. …
1. compareTo(Object) belongs to which class? 1. Collections 2. Comparator 3. Comparable 4. Arrays 2. singletonList(Object) method is defined in? 1. class ArrayList 2. interface List 3. interface Collection 4. class Collections 3. When a thread is started with start() method, in which state it exists? 1. born state 2. runnable state 3. …
