Java Interview Questions

Java Interview Questions

1. Java Multithreading
   Process can be further divided into small tasks which refer as a Thread. If two or more tasks of a process executes concurrently, then this scenario refers as aMultithreading environment.
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2. Recursion Recursion is one of the interesting topic. The problems, which can be implemented using loops, can be implemented with Recursion as well.
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3. Singleton Design Pattern
   The Singleton class means whose only one instance can be created. To make the class Singleton, we should restrict the ways through which the objects can be created. The object can be created in the following ways -
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4. Static and Non Static Synchronized Methods

   Static Method Call - When we make a call to a static method (either directly from class or any object of that class), the Class object of that Class involves in that call. Every Class has only one Class object.
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5. Synchronous and Asynchronous Exceptions
    The interpreter executes the java program sequentially. An exception E can occur relative to a line (L) of program.
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6. Checked Vs Unchecked Exception
   Checked Exception  in Java is all those Exception which requires being catches and handled during compile time. If Compiler doesn't see try or catch block handling a Checked Exception
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7. System.out.println
   System – is a final class and cannot be instantiated. Therefore all its members (fields and methods) will be static and we understand that it is an utility class.Show Complete Answer
8. Can a top level class be private or protected
   No. A top level class can not be private or protected. It can have either "public" or no modifier.
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9. main() method in java
   The main function is important function in Java programming language.
   The main method is the first method,
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10. Path and Classpath
    PATH is nothing but setting up an environment for operating system.   Operating System will look in this PATH for executable.Show Complete Answer
11. JDBC Connection in Java
    JDBC (Java DataBase Connectivity) is an API for the Java programming language through which the databse can be accessed using methods for querying and updating data.Show Complete Answer
12. Iterate a HashMap
    HashMap is an object that stores both “key/value” as a pairs.
    It is one of the most useful data structures in the Java programming language.Show Complete Answer
13. JNDI
    The Java Naming and Directory Interface (JNDI) is part of the Java platform, providing applications based on Java technology with a unified interface to multiple naming and directory services. Show Complete Answer
14. Extract a list of filtered files in Java
    Sometimes, we need to get a list of files exist within a directory as per our criteria like filename, file extension, last modified date or other attributes. It reduces the overhead to filter them after getting the list using our code.
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