Explain features of Java/Java Buzzwords.

-

 JAVA BUZZWORDS /features of Java

The primary objective of Java programming language creation was to make it a portable, simple, and secure programming language. Apart from this, there are also some excellent features which play an important role in the popularity of this language. The features of Java are also known as java buzzwords. Here are some terms that are used for java as its features:

Simple: According to Sun, Java language is simple because its syntax is similar to C and C++ and hence easy to learn after C and C++. Again confusing and rarely used features, such as explicit pointers, operator overloading, etc, are removed from java.

Object-Oriented: Object-oriented means we organize our software as a combination of different types of objects that incorporate both data and behavior. Java is a true object-oriented programming language that supports encapsulation, inheritance, and polymorphism. Almost everything in Java is an object.

Distributed: We can create distributed applications in java. Remote Method Invocation (RMI) and Enterprise Java Beans (EJB) are used for creating distributed applications. We may access files by calling the methods from any machine on the internet.

Robust: Robust simply means strong. Java uses strong memory management. There is a lack of pointers that avoids security problem. There is automatic garbage collection in java. There is an exception handling and type checking mechanism in java. All these points make java robust.

Secure: Security is an important concern since Java is meant to be used in networked environments. Applets running in a Web browser cannot access a Web client's underlying file system or any other Web site other than that from which it originated. Again, Java programs run in a virtual machine that protects the underlying operating system from harm. Also, the absence of pointers in Java ensures that programs cannot gain access to memory locations without proper authorization. . Furthermore, access restrictions are enforced (public, private) and byte codes are verified, which copes with the threat of a hostile compiler.

Architecture Neutral: Since Java runs inside of a Virtual Machine, the program does not depend on the underlying operating system or hardware. Java code can be run on multiple platforms such as Windows, Linux, Sun Solaris, Mac/OS, etc. Java code is compiled by the compiler and converted into bytecode. This bytecode is a platform-independent code because it can be run on multiple platforms. The phrase writes once, run anywhere is the major concept for the portability that Java adheres. This is because byte code will run on any operating system for which there exists a compatible Virtual Machine.

Compiled and Interpreted: Usually, computer language is either compiled or interpreted. Java combines both these approaches thus making Java a two-stage system. First, the Java compiler translates source code into what is known as bytecode instructions. Byte codes are not machine instructions and therefore, in the second stage, the Java Interpreter generates machine code that can be directly executed by the machine that is running the Java program.

High Performance: Java is faster than traditional interpretation since byte code is "close" to native code still somewhat slower than a compiled language (e.g., C++). The performance gain is due to the JIT (Just In Time) compilation that caches the recurring process to speed up the interpretation.

Multithreaded: We can write Java programs that deal with many tasks at once by defining multiple threads. The main advantage of multi-threading is that it shares the same memory. Threads are important for multi-media, Web applications, etc.

Comments

Post a Comment

Popular posts from this blog

What are different steps used in JDBC? Write down a small program showing all steps.

-
 T he fundamental steps involved in the process of connecting to a database and executing a query consist of the following: Import JDBC packages. Load and register the JDBC driver. Open a connection to the database. Create a statement object to perform a query. Execute the statement object and return a query resultset. Process the resultset. Close the resultset and statement objects. Close the connection. These steps are described in detail in the sections that follow. 1. Import JDBC Packages This is for making the JDBC API classes immediately available to the application program. The following import statement should be included in the program irrespective of the JDBC driver being used: import java.sql.*; Additionally, depending on the features being used, Oracle-supplied JDBC packages might need to be imported. For example, the following packages might need to be imported while using the Oracle extensions to JDBC such as using advanced data types such as BLOB, and so on. import o...
Read more

Explain Parallel Efficiency of MapReduce.

-
Image
 PARALLEL EFFICIENCY OF MAP-REDUCE It is worth trying to figure out what is the parallel efficiency of MapReduce. Now let us assume that the data produced after the map phase is σ times the original data size D (σD), further, we assume that there are P processors which in turn perform map and reduce operations depending on which phase they are used in, so we do not have any wastage of processors. Also, the algorithm itself is assumed to do wD useful work, w is not necessarily a constant it could be D^2 or something like that, but the point is that there is some amount of useful work being done even if you have a single processor and that's wD. Now let us look at the overheads of doing the computation wD using MapReduce. After the map operation, instead of D data items, we have σD data items in P pieces, so each mapper writes data to their local disk. So, P there is some overhead associated with writing this data. Next, this data has to be read by each reducer before it can begin ...
Read more

Suppose that a data warehouse for Big-University consists of the following four dimensions: student, course, semester, and instructor, and two measures count and avg_grade. When at the lowest conceptual level (e.g., for a given student, course, semester, and instructor combination), the avg_grade measure stores the actual course grade of the student. At higher conceptual levels, avg_grade stores the average grade for the given combination. a) Draw a snowflake schema diagram for the data warehouse. b) Starting with the base cuboid [student, course, semester, instructor], what specific OLAP operations (e.g., roll-up from semester to year) should one perform in order to list the average grade of CS courses for each BigUniversity student. c) If each dimension has five levels (including all), such as “student < major < status < university < all”, how many cuboids will this cube contain (including the base and apex cuboids)?

-
Image
a) A Snowflake Shema is shown in figure below: b) The specific OLAP operations to be performed: 1. Roll-up on course from course_id to department. 2. Roll-up on a student from student_id to university. 3. Dice on course, student with department ="CS" and university = "biguniversity" 4. Drill-down on a student from the university to student_name. c) N = 4 dimensions The cube will contain 54 = 625 cuboids.
Read more