Technology Questions

the layer that establishes ,manages and terminates the session between two communticating devices

Dalvik serves as a virtual machine, and it is where every Android application runs. Through Dalvik, a device is able to execute multiple virtual machines efficiently through better memory management.

1.Main difference is methods of a Java interface are implicitly abstract and cannot have implementations. A Java abstract class can have instance methods that implements a default behavior.

2.Variables declared in a Java interface is by default final. An abstract class may contain non-final variables.

3.Members of a Java interface are public by default. A Java abstract class can have the usual flavors of class members like private, protected, etc..

4.Java interface should be implemented using keyword “implements”; A Java abstract class should be extended using keyword “extends”.

5.An interface can extend another Java interface only, an abstract class can extend another Java class and implement multiple Java interfaces.

6.A Java class can implement multiple interfaces but it can extend only one abstract class.

7.Interface is absolutely abstract and cannot be instantiated; A Java abstract class also cannot be instantiated, but can be invoked if a main() exists.

8.In comparison with java abstract classes, java interfaces are slow as it requires extra indirection.

Aggregate functions perform a calculation on a set of values and return a single value. Aggregate functions ignore NULL values except COUNT function. HAVING clause is used, along with GROUP BY, for filtering query using aggregate values.

Following functions are aggregate functions. 

AVG, MIN CHECKSUM_AGG, SUM, COUNT, STDEV, COUNT_BIG, STDEVP, GROUPING, VAR, MAX. VARP

The standard query operators in LINQ are the extension methods that form the LINQ pattern. These operators form an API that enables querying of any .NET array or collection. It operates on sequences and allows you to perform operations, such as determining if a value exists in the sequence and performing an aggregated function, such as a summation over a sequence.

public class Test {

    public void replaseSpaces(char[] str, int length) {

        int spaceCount = 0, newLength = 0, i = 0;

        for(i = 0; i < length; i++) {

            if (str[i] == ' ') 

                spaceCount++;

        }

        newLength = length + (spaceCount * 2);

        str[newLength] = '\0';

        for(i = length - 1; i >= 0; i--) {

            if (str[i] == ' ') {

                str[newLength - 1] = '0';

                str[newLength - 2] = '2';

                str[newLength - 3] = '%';

                newLength = newLength - 3;

            }

            else {

                str[newLength - 1] = str[i];

                newLength = newLength - 1;

            }

        }

        System.out.println(str);

    }

    public static void main(String[] args) {

        Test tst = new Test();

        char[] ch = {'t', 'h', 'e', ' ', 'd', 'o', 'g', ' ', ' ', ' ', ' ', ' ', ' '};

        int length = 6;

        tst.replaseSpaces(ch, length);  

    }

}

Oracle constraints are used to maintain consistent of data and ensure the data is properly maintained. A constraint is more or less a restriction we try to apply on a table.
Types of constraints:
- Check constraints
- NOT NULL constraint
- PRIMARY KEY constraint
- REFERENCES constraint
- UNIQUE constraint

The QA testing process that was followed in my last company where I worked was like this: First of all the Business Requirement Document was prepared as per the client’s requirement (with the muck-up screen shots). Then on the basis of the requirement document, Test Strategy, Test Plans and Test Cases were written in sequential order. Once the Build is made and deployed to the different testing environments where different types of testing were performed to check whether there are any defects.