Both interfaces are used for implement serialization. But, the basic difference is Serializable interface does not have any method (it’s a marker interface ) and Externalizable interface having 2 methods such as readExternal() and writeExternal(). Serializable interface is the super interface for Externalizable interface.
An abstract method is a method whose implementation is deferred to a subclass.
A (non-local) inner class may be declared as public, protected, private, static, final, or abstract.
The read() method returns -1 when it has reached the end of a file.
A private variable may only be accessed within the class in which it is declared.
As per my knowledge there are basically 3 types of class loader like bootstarp classloader,extension class loader and system class loader.
Give your own choice. Also mention a valid reason for why you are interested for that location. The reason should be always positive and clear. Example :- you can support your family from this location,
Two methods may not have the same name and argument list but different return types.
Downcasting is the casting from a general to a more specific type, i.e. casting down the hierarchy.
Trient variable can’t be serialize. For example if a variable is declared as trient in a Serializable class and the class is written to an ObjectStream, the value of the variable can’t be written to the stream instead when the class is retrieved from the ObjectStream the value of the variable becomes null.
Basically iterator access process the traverse operation through each element, where index access process access direct the element by using the index.
The Collection API is a set of classes and interfaces that support operation on collections of objects. These classes and interfaces are more flexible, more powerful, and more regular than the vectors, arrays, and hashtables if effectively replaces.
Example of classes: HashSet, HashMap, ArrayList, LinkedList, TreeSet and TreeMap.
Example of interfaces: Collection, Set, List and Map.
Reflection is one of the most powerful api which help to work with classes, methods and variables dynamically. Basically it inspect the class attributes at runtime. Also we can say it provides a metadata about the class.
You can describe any issue you faced during your project work in the organization. And what the solution you have implemented for that issue.
The Object class is extended by all other classes.
It is referred to as the modulo or remainder operator. It returns the remainder of dividing the first operand by the second operand.
Because, character array stores data in encrypted format which is not readable by human. But,the string stores the data in human readable format which is not secure.
You can use ImageIo.read() and ImageIO.write() method of javax.imageio package.
A daemon thread is normally runs on background. And it does not prevent the JVM from exiting when the program finishes but the thread is still running.
Unicode requires 16 bits and ASCII require 7 bits. Although the ASCII character set uses only 7 bits, it is usually represented as 8 bits. UTF-8 represents characters using 8, 16, and 18 bit patterns. UTF-16 uses 16-bit and larger bit patterns.
First you should try to convince that this company gives huge opportunity in many aspect i.e. new technologies implementation, the policy of company suits you like professionalism. Also you can mention that you are big fan of this company and its your dream company. Basically show your all positive attitude towards company.
These are accessibility modifiers. Private is the most restrictive, while public is the least restrictive. There is no real difference between protected and the default type (also known as package protected) within the context of the same package, however the protected keyword allows visibility to a derived class in a different package.
Yes. We can throw checked exception.
An object reference be cast to an interface reference when the object implements the referenced interface.
There are two types of casting, casting between primitive numeric types and casting between object references. Casting between numeric types is used to convert larger values, such as double values, to smaller values, such as byte values. Casting between object references is used to refer to an object by a compatible class, interface, or array type reference.
A non-static inner class may have object instances that are associated with instances of the class’s outer class. A static inner class does not have any object instances.
The basic design of ConcurrentHashMap is to handling threading. Basically it locks each of the box (by default 16) which can be locked independently and thread safe for operation. And it does not expose the internal lock process.
The non-Unicode letter characters $ and _ may appear as the first character of an identifier.
A package statement must appear as the first line in a source code file (excluding blank lines and comments).
No, an object cannot be cast to a primitive value.