Top Core Java Interview Questions| Top SQL Interview Questions| MOST ASKED|

1. What if I write static public void instead of public static void in java?
The program compiles and runs correctly because the order of specifiers doesn't matter in Java.

2. What are the various access specifiers in Java?
In Java, access specifiers are the keywords which are used to define the access scope of the method, class, or a variable. In Java, there are four access specifiers given below.

Public The classes, methods, or variables which are defined as public, can be accessed by any class or method.

Protected Protected can be accessed by the class of the same package, or by the sub-class of this class, or within the same class.

Default Default are accessible within the package only. By default, all the classes, methods, and variables are of default scope.

Private The private class, methods, or variables defined as private can be accessed within the class only.
3. What is an object?
The Object is the real-time entity having some state and behavior. In Java, Object is an instance of the class having the instance variables as the state of the object and the methods as the behavior of the object. The object of a class can be created by using the new keyword.
4. what are the different phases of STLC
Phase 1: Requirement Analysis.
Phase 2: Test Planning.
Phase 3: Test Case Development.
Phase 4: Test Environment Setup.
Phase 5: Test Execution.
Phase 6: Test Cycle Closure.

6. What is Concurrency Testing?
Concurrency Testing is defined as a testing technique to detect the defects in an application when multiple users are logged in. In other words monitoring the effect while multiple users perform the same action at the same time
7. Correct Keyword Order in SQL
SQL is extremely sensitive to keyword order.
So make sure you keep it right:
1. SELECT
2. FROM
3. WHERE
4. ORDER BY
5. LIMIT
8. What are the types of operators available in SQL?
Operators are the special keywords or special characters reserved for performing particular operations and are used in the SQL queries. There is three type of operators used in SQL:

Arithmetic operators: addition (+), subtraction (-), multiplication (*), division (/), etc.
Logical operators: ALL, AND, ANY, ISNULL, EXISTS, BETWEEN, IN, LIKE, NOT, OR, UNIQUE.
Comparison operator:
9.Write an SQL query to find names of employee start with 'A'?
SELECT * FROM Employees WHERE EmpName like 'A%'
10. What is the difference between NULL value, zero and blank space?
Ans: A NULL value is not the same as zero or a blank space. A NULL value is a value which is 'unavailable, unassigned, unknown or not applicable.' On the other hand, zero is a number, and a blank space is treated as a character.
11. Which function is used to return remainder in a division operator in SQL?
The MOD function returns the remainder in a division operation.

12. How many types of constructors are used in Java?
Based on the parameters passed in the constructors, there are two types of constructors in Java.

Default Constructor: default constructor is the one which does not accept any value. The default constructor is mainly used to initialize the instance variable with the default values. It can also be used for performing some useful task on object creation. A default constructor is invoked implicitly by the compiler if there is no constructor defined in the class.

Parameterized Constructor: The parameterized constructor is the one which can initialize the instance variables with the given values. In other words, we can say that the constructors which can accept the arguments are called parameterized constructors.

13. What are the restrictions that are applied to the Java static methods?
Two main restrictions are applied to the static methods.

The static method can not use non-static data member or call the non-static method directly.
this and super cannot be used in static context as they are non-static.
14. Why is the main method static?
Because the object is not required to call the static method. If we make the main method non-static, JVM will have to create its object first and then call main() method which will lead to the extra memory allocation.
15. Can we override the static methods?
No, we can't override static methods.
16. what is load testing & stress testing

17. What is Exploratory Testing?
EXPLORATORY TESTING is a type of software testing where Test cases are not created in advance but testers check system on the fly. They may note down ideas about what to test before test execution. The focus of exploratory testing is more on testing as a "thinking" activity.

Exploratory Testing is widely used in Agile models and is all about discovery, investigation, and learning.

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