Who invented java? When?
 Tell me java features?
 What is platform?
 What is platform independent and platform dependent?
 What is procedure oriented language?
 What is object oriented language?
 What is JVM?Why?
 Is JVM platform independent?
 Difference between JDK and JRE?
 What is the java latest version?
 Difference between minor version and major version?
 What is JAVA-HOME means?
 What is the difference between binary files and library files?
 What is the difference between path and classpath?
 Can we save java file other than class name?
 If java file has multiple classes what is the java file name?
 In a single java file how many public classes we can define?
 Is main method mandatory to compile and run java program fine?
 Can we compile and run empty java file?
 Can we have main method in all classes of a single java file ?
 Can we call one class main method from another class main method?
 What is naming conventions? Explain about it?
 What topics are eliminated from java compared with C and C++?
 What is JIT compiler?
 In main method signature is public static order mandatory?

Java data types

 How many types of data types are there?
 What are the primitive data types?
 What are the referenced data types?
 Why referenced types are given, when we have primitive types?
 What are the limitations of array?
 What is literal?
 What are the different types of literals?
 What is the size of the Boolean type?
 What is the difference between float and double?
 What is type conversion?
 What are the different types of conversions?
 What is implicit conversion and explicit conversion?
 Can we store long variable in float?
 If we assign char literal to number variable, what happened?
 If we assign number variable to char variable, what happened?
 Can we assign int variable to char variable directly?
 What is automatic type promotion?
 What is the overloaded operator in java?
 is java % pure object oriented language ?
 what is auto boxing and auto unboxing?
 What are the different accessibility levels?
 What are the accessibility modifiers allowed with the class?
 What are the access specifiers allowed with the interface?
 What are the access specifiers allowed with the interface members?
 What is the purpose of the return statement?
 What is variable?
 Define object?
 What are the different types of variables ?
 What are the different types of class level variables?
 What is static variable?
 Can we access local variables without initialization?
 Can we access global variables without initialization?
 How can we access non static variables and method of a class?
 How can we access static variables and methods of a class?
 Can we access static members using object of a class?
 Can we declare local variable as static?
 What is final variables?
 What is transient variable?
 What is volatile variable?
 When static variables gets memory?
 When non static variables gets memory?
 Can we use final with static keyword?
 What comes first final? Or static?
 In what area all the static variables will be created?
 In what area all the non static variables will be created?
 In what area local variables will be created?
 In what area objects will be created?
 If object is created in method, then in what area it will be created?
 What is native method?
 What is the scope of static variables?
 What is shadowing?
 What is static block?
 Who will execute static block?
 How many static blocks we can define in a class?
 What is the execution order of static blocks
 Can we execute class logic without main method?
 Why main method is public?
 Explain public static void main(String args[])?
 Why main method return type is void?
 What is the execution order of static block , static variable and main method?
 What are the different types of non static members?
 What is the output printed if we print object?
 Why can’t we call non static methods from static methods?
 Tell me about this?
 What is pass by value and pass by reference?
 Is java support pass by reference?
 Can we use this keyword in static method?
 Can we initialize this with any reference ? why?
 Define constructor?
 Can constructor throws exception?
 Can we return value in constructor?
 Can we write return; statement in constructor?
 Is it possible to create method name with the class name?
 How can compiler and JVM differentiate constructor and method if both have same name?
 Should we create constructor in class?
 If we create parameterized constructor, will compiler create default constructor?
 What is the accessibility modifier of default constructor?
 What are the differences between default constructor and no-argument constructor?
 What is constructor overloading?
 When the non static block will be executed?
 What is the execution order of all static members?
 What happened if we create object in non static block?
 Can we call static method with null referenced variable?
 Can we call non static methods and variables with null referenced variables?
 What is the referenced object and un referenced object?
 What type of objects are destroyed by JVM?
 What is the purpose of the garbage collector?
 How can you make objects available for garbage collector?
 Can we force garbage collector for it’s execution?
 How can we request JVM for garbage collection execution?
 Who controls garbage collector?
 Explain about finalize() method?
 Who calls finalize() method?
 Can we disable execution of finalize() while object is destroyed? how?
 What is the difference between reference variables and primitive variables?
 What is array? adventage of array?
 What are the drawbacks of array?
 How the garbage collector works with arrays?
 What happened if you declare array as final?
 What is the difference between length, length();
 How can we sort the array elements?
 Explain the command javac -d . filename.java?
 What happened if you add String to int?
 What is the super class for all classes?
 What methods of Object class we can override?
 What is the return type of equals()?
 What is the return type of hashcode()?
 Why equals() method is given when == operator is already there to compare object references?
 What is cloning?
 How can we clone object?
 What is shallow cloning ?
 What is deep cloning?
 What is wrapper class?
 How many wrapper classes are there? What are those?
 How can we convert primitive data type to Wrapper class object type?
 How can we convert Wrapper class object type to primitive data type?
 How can we convert primitive String object to wrapper class object type?
 Which primitive String object can’t be converted into wrapper class object type?
 How can we convert wrapper class object type to String object type?
 What is widening?
 What is stream?
 What are the different types of streams based on data flow? Define them?
 What are the different types of streams based on data passed? Define them?
 what is reader and writer?
 Differences and commonalities between Reader and InputStream?
 Differences and commonalities between Writer and OutputStream?
 why FileInputStream and FileOutputStream?
 Why DataOutputStream and DataInputStream?
 Why Object InputStream and ObjectOutputStream?
 What is serialization?
 What is deserialization?
 What is the rule on serialization?
 What are the different types of serializations?
 What is marker interface?
 What is the need of marker interface?
 System.out.print(); is this statement will be executed fine?
 System.out.println(null); is this statement executed fine?
 What are the default stream objects are created by the class System?
 What is FileReader and FileWriter?
 What is the limitation of FileReader?
 Explain about enum,Enum,Enumeration?
 Explain about finally,final,finalize?
 What is the difference between i++ and i=i+;

Java comments , identifiers , keywords

 Why comments in java
 What are the different types of comments in java
 Will compiler generate byte code for comments
 What is identifier in java
 What are the rules to define an identifier
 What is keyword ?
 What are the rules to define keyword?
 Is null keyword ?
 Can we use null as identifier