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Transferring the information between MySQL and data files mean importing data from data files into our database or exporting data from our database into files. MySQL is having two commands that can be used to import or export data between MySQL and data files through the command line −mysqlimport Actually, mysqlimport command reads a spread of data formats, including comma-and tab-delimited, and inserts the information into a database. In other words, we can say that it provides a command-line interface for importing the data i.e. command-line interface to the LOAD DATA INFILE statement. Its syntax would be as follows −SyntaxMysqlimport [options] ... Read More
No, we cannot write any statements in between try, catch and finally blocks and these blocks form one unit. The functionality of try keyword is to identify an exception object and catch that exception object and transfer the control along with the identified exception object to the catch block by suspending the execution of the try block. The functionality of the catch block is to receive the exception class object that has been sent by the try and catch that exception class object and assigns that exception class object to the reference of the corresponding exception class defined in the catch block. The finally blocks are ... Read More
Immutable objects are those objects whose states cannot be changed once initialized. Sometimes it is necessary to make an immutable class as per the requirement. For example, All primitive wrapper classes (Integer, Byte, Long, Float, Double, Character, Boolean and Short) are immutable in Java. String class is also an immutable class.To create a custom immutable class we have to do the following stepsDeclare the class as final so it can’t be extended.Make all fields private so that direct access is not allowed.Do not provide setter methods (methods that modify fields) for variables, so that it can not be set.Make all mutable ... Read More
The Throwable class is a superclass of all errors and exceptions in Java. Objects that are instances of this class are thrown by the Java Virtual Machine or can be thrown by a throw statement. Similarly, this class or one of its subclasses can be the argument type in a catch clause.Instances of two subclasses Error and Exception are used to indicate that exceptional situations have occurred, these instances are created in the context of the exceptional situation to include relevant information.Commonly used exception methods of Throwable classpublic String getMessage(): returns the message string about the exception.public Throwable getCause(): returns the cause of the exception. ... Read More
Yes, we can declare the main () method as final in Java. The compiler does not throw any error.If we declare any method as final by placing the final keyword then that method becomes the final method.The main use of the final method in Java is they are not overridden.We can not override final methods in subclasses.If we are using inheritance and we need some methods not to overridden in subclasses then we need to make it final so that those methods can't be overridden by subclasses.We can access final methods in the subclass but we can not override final methods.Exampleclass BaseClass ... Read More
MySQL returns a specified number of characters of a string with the help of LEFT() and RIGHT() functions.MySQL LEFT() function will return the specified number of characters from the left of the string.SyntaxLEFT(str, length)Here str is the string from which a number of characters would be returned and the length is an integer value which specifies how many characters to be returned.Examplemysql> Select LEFT('My Name is Ram', 7); +---------------------------+ | LEFT('My Name is Ram', 7) | +---------------------------+ | My Name | +---------------------------+ 1 row in set (0.00 sec)MySQL RIGHT() function will ... Read More
AWT stands for Abstract Window ToolKit and it supports Java GUI programming. It is a portable GUI library for Stand-alone Java applications/applets. The AWT provides the connection between our application and the native GUI while Java Swing implements a set of GUI components that build on AWT technology and it can provide a pluggable look and feel. Java Swing is implemented entirely in the Java programming language.First of all, by a heavy-weight, it means the code will take comparatively more time to load and it will consume more System resources. AWT is considered to be heavy-weight because its components are dependent ... Read More
As we know that certain objects within MySQL are known as identifiers. These objects include a database, table, index, column, alias, view, stored procedure, partition, tablespace etc. Identifiers are stored using Unicode (UTF-8). The maximum length of each type of identifier is given in the following table:Sr. No.IdentifierMaximum Length (characters)1Database642Table643Column644Index645Constraint646Stored Procedure or Function647Trigger648View649Event6410Tablespace6411Log File Group6412Alias25613Compound Statement Label16
A Java program can be classified into two types, one is an Application and another is an Applet.ApplicationAn application is a stand-alone java program that runs with the support of a virtual machine in a client or server-side.A java application is designed to perform a specific function to run on any Java-compatible virtual machine regardless of the computer architecture.An application is either executed for the user or for some other application program.Examples of java applications include database programs, development tools, word processors, text and image editing programs, spreadsheets, web browsers, etc.Examplepublic class Demo { public static void main(String args[]) ... Read More
Every class object is created using the same new keyword, so it must have information about the class to which it must create an object. For this reason, the constructor name should be the same as the class name.Exampleclass MyConstructor{ public MyConstructor() { System.out.println("The constructor name should be same as the class name"); } public static void main(String args[]){ MyConstructor mc = new MyConstructor(); } }In the above program, the constructor name should be the same as the class name (MyConstructor).OutputThe constructor name should be same as the class name