75 IMP Java Questions

Java Freshers Top 75 Core Java Intervie Questions List Java Interview Questions

1.Can Java thread object invoke start method "twice" ? 
2.Give the list of Java Object class methods ?
3.Can we call servlet destory() from service() ? 
4.Can we override a static method ? 
5.Can you list "Serialization" Interface methods ?
6.What is the difference between super() and this() ? 
7.How to prevent a method from being overridden ? 
8.Can we create abstract classes without any abstract methods ? 
9.Explain private,protected,public ? 
10.Can we have static methods in interface ?
11.What is transient variable ?
12.Incase, there is a return at the end of try block, will execute finally block ? 
13.What is abstract class or abstract method ?
14.What is default value of a boolean ?
15.When to use LinkedList or ArrayList ? 
16.What is daemon thread ? 
17.Does each thread in java uses seperate stack ? 
18.What is the difference between Enumeration and Iterator ?
19.Does system.exit() in try block executes finally block ? 
20.What is fail-fast in Java ? Explain ? 
21.What is final, finally and finalize ?
22.In java, are true and false keywords ?
23.What is the purpose of "Garbage Collection" ? 
24.What are the types of ResultSet ?
25.What is difference between "wait" and "sleep" methods in Java ? 
26.What is servlet context ? 
27.What happens if one of the members in a class does not implement Serializable interface ?
28.What is race condition ? 
29.How to get current time in milli seconds ?
30.How can you convert Map to List ? 
31.What is strictfp keyword ?
32.What is System.out in Java ? 
33.What is difference between ServletOuptputStream and PrintWriter ? 
34.What is Java static import ? 
35.When to use String and StringBuffer ? 
36.What is difference between StringBuffer and StringBuilder ? 
37.What is wrapper class in Java ? 
38.Is Iterator a Class ? 
39.What is Java classpath ? 
40.Can a class in Java be marked as private ? 
41.Is null a keyword in Java ? 
42.What is the initial state of a thread when it is started ? 
43.What is the super class for Exception and Error ?
44.What is Class.forName() ? 45.Can interface be final ? 
46.What is the difference between exception and error ?
47.What is default value of a local variables ?
48.What is local class in Java ? 
49.Can we initialize uninitialized final variable ?
50.Can we declare abstract method as final ?
51.Can we have finally block without catch block ?
52.What is pass by value and pass by reference ?
53.Can we declare main method as private ? 
54.What is the difference between preemptive scheduling and time slicing ?
53.Can non-static member classes (Local classes) have static members ?
54.What are the environment variables do we neet to set to run Java ?
55.Can you serialize static fields of a class ? 
56.What is the difference between declaring a variable and defining a variable ?
57.Where can we use serialization ?
58.What modifiers are allowed for methods in an Interface ?
59.What is the purpose of Runtime and System class ? 
60.Which one is faster ? ArrayList or Vector ? Why ? 
61.What is the difference between "Static Synchronized" and "Synchronized" methods ?
62.What is the order of catch blocks when catching more than one exception ? 
63.What is the difference between the prefix and postfix forms of the increment(++) operator ? 
64.What is hashCode ? 65.What is the difference between Hashtable and HashMap ?
66.What are the restrictions when overriding a method ? 67.What is the use of assert keyword ? 
68.What is difference between break, continue and return statements ? 
69.What is the difference between while and do-while statements ?
70.When does the compiler provides the default constructor ?
71.How to create and start a thread in Java ? 
72.Can I extend a "Final" class in Java ? 
73.Explain "volatile" keyword in Java ?
74.Can we catch "RuntimeException" ? What is "Checked" and "Unchecked" Exception ? 
75.When to make a constructor "private" and why ?