What is exception handling in JSP?
The exception is normally an object that is thrown at runtime. Exception Handling is the process to handle the runtime errors. There may occur exception any time in your web application. So handling exceptions is a safer side for the web developer. In JSP, there are two ways to perform exception handling:
What is @errorerrorpage in JSP?
errorPage: It is a separate error page we can write to handle exceptions which are showing exception class name, error message, and exception stack trace. If our main JSP page throws an exception it will redirect you to the specified error handling page.
What are the disadvantages of JSP?
Disadvantage: As the JSP page is used to represent the view layer so it is not a good practice to use Java code directly into JSP pages. If we want to handle exceptions for more than one JSP page then we need to duplicate try-catch blocks in every JSP page which is not an efficient approach.
What is the difference between exception handling and exception throwing?
The exception is normally an object that is thrown at runtime. Exception Handling is the process to handle the runtime errors. There may occur exception any time in your web application.
What is exception handling in JSP?
Exception Handling is the process to handle the runtime errors. There may occur exception any time in your web application. So handling exceptions is a safer side for the web developer. In JSP, there are two ways to perform exception handling: By errorPage and isErrorPage attributes of page directive.
What are the two common exceptions in JSP?
There are two ways of handling exceptions in JSP. They are: By errorPage and isErrorPage attributes of page directive.
What happens if an exception is thrown from a JSP?
Whenever the page throws an exception, the JSP container automatically invokes the error page.
What is JSP explain with an example?
JSP (JavaServer Pages) is server side technology to create dynamic java web application. JSP can be thought as an extension to servlet technology because it provides features to easily create user views. JSP Page consists of HTML code and provide option to include java code for dynamic content.
What do you mean by JSP processing?
It is an advanced version of Servlet Technology. It is a Web-based technology that helps us to create dynamic and platform-independent web pages. In this, Java code can be inserted in HTML/ XML pages or both. JSP is first converted into a servlet by JSP container before processing the client's request.
What is difference between JSP and servlet?
Servlets are faster as compared to JSP, as they have a short response time. JSP is slower than Servlets, as the first step in the JSP lifecycle is the conversion of JSP to Java code and then the compilation of the code. Servlets are Java-based codes. JSP are HTML-based codes.
How do I debug a JSP file?
ProcedureIn the Project Explorer view, open your JSP file. ... Verify that you are using the Source page of the editor. ... From the JSP file's context menu in the Project Explorer view, click Debug As> Debug on Server. ... In the Debug view, step through the code and make the necessary changes to the JSP file. ... Save the JSP file.More items...
What is JSP action tags?
JSP Action TagsJSP Action TagsDescriptionjsp:forwardforwards the request and response to another resource.jsp:includeincludes another resource.jsp:useBeancreates or locates bean object.jsp:setPropertysets the value of property in bean object.4 more rows
How is JSP used in MVC model?
In this article, we have learnt about the MVC i.e. Model View Controller architecture. JSP plays the role of presentation of the data and controller. It is an interface between model and view while model connects both to the controller as well as the database. Main business logic is present in the model layer.
What is JSP and why do we need it?
JavaServer Pages (JSP) is a technology for developing Webpages that supports dynamic content. This helps developers insert java code in HTML pages by making use of special JSP tags, most of which start with <% and end with %>.
What is JSP in JavaScript?
JSP stands for Java Server Pages, are a dynamic web technology based on servlet container and Java EE specification which is used to generate dynamic web content in webpages.
What is a JSP file?
Jakarta Server Pages (JSP; formerly JavaServer Pages) is a collection of technologies that helps software developers create dynamically generated web pages based on HTML, XML, SOAP, or other document types. Released in 1999 by Sun Microsystems, JSP is similar to PHP and ASP, but uses the Java programming language.
What are the type of exception in Java?
There are mainly two types of exceptions in Java as follows: Checked exception. Unchecked exception.
What are the different types of errors in JSP?
Exceptions in JSP are of three types: Checked Exception. Runtime Exception. Error Exception.
What are the JSP scripting elements?
There are three main subdivisions of scripting elements in JSP.Expression Tags.Scriptlet Tags.Declaration Tags.
What are the tags in JSP?
A tag file is a source file that contains a fragment of JSP code that is reusable as a custom tag. Tag files allow you to create custom tags using JSP syntax. Just as a JSP page gets translated into a servlet class and then compiled, a tag file gets translated into a tag handler and then compiled.
What is an exception object?
The exception object is an instance of a subclass of Throwable (e.g., java.lang. NullPointerException) and is only available in error pages. Following table lists out the important methods available in the Throwable class.
What is a checked exception?
Checked exceptions. A checked exception is an exception that is typically a user error or a problem that cannot be foreseen by the programmer. For example, if a file is to be opened, but the file cannot be found, an exception occurs. These exceptions cannot simply be ignored at the time of compilation.
What is runtime exception?
A runtime exception is an exception that probably could have been avoided by the programmer. As opposed to the checked exceptions, runtime exceptions are ignored at the time of compliation.
Can you use JSTL tags to write an error page?
You can make use of JSTL tags to write an error page ShowError.jsp. This page has almost same logic as in the above example, with better structure and more information −
What are checked exceptions?
Exceptions that users make are called checked exceptions. It also includes exceptions that a programmer and developer can’t see. For example, a file that needs to be compiled can’t be found. The compiler can’t ignore these exceptions at the time of compilation. Other examples can be an IO Exception or an SQL Exception.
What are the errors that are ignored in compiler?
One cannot do anything about it. These include Instantiation error, Internal error, Stack Overflow, etc.
Can compilers avoid exceptions?
Unlike checked exceptions, compilers may avoid these exceptions at the compilation time. This exception might have been avoided by the developer or programmer. Errors like Arithmetic exception, Null Pointer exception, ArrayIndexOutOfBounds exception fall under this category.
What is an exception in a program?
Exceptions are the run time errors that occur during the execution of the program. It is an unexpected event that interrupts the normal flow of the program which is throws at runtime. When an exception occurs, program execution gets terminated.
What is exception handling?
Exception Handling is the process of handling the statements or skipping the statements which may generate exceptions and providing an alternative solution, continue with the rest of the program and close / terminate the program normally.
What is error page?
errorPage: It is a separate error page we can write to handle exceptions which are showing exception class name, error message, and exception stack trace. If our main JSP page throws an exception it will redirect you to the specified error handling page.
What is a checked exception?
Exceptions that identified at compilation time and occurred at runtime are called checked exceptions. It is also called Compile Time Exceptions. An exception said to be checked exception whose exception handling is mandatory as per the compiler. Examples: IOException, ClassNotFoundException, CloneNotSupportedException, etc.
What is page level exception handling?
In page-level exception handling, we are using page directives to specify separate error pages. If an exception occurs in the JSP page it will redirect you to a separate error page. There are following two elements of Page Directives used for handling exceptions:
What are compiler errors?
Errors that occur at the time of compilation of the program are called compile-time errors. Compile-time errors occurred because if we don’t follow the java syntaxes properly, java programming rules properly, etc. Compile-time errors are identified by the java compiler.
Is it a good practice to use Java code directly into JSP pages?
Disadvantage: As the JSP page is used to represent the view layer so it is not a good practice to use Java code directly into JSP pages. If we want to handle exceptions for more than one JSP page then we need to duplicate try-catch blocks in every JSP page which is not an efficient approach.
What is exception handling?
The exception is normally an object that is thrown at runtime. Exception Handling is the process to handle the runtime errors. There may occur exception any time in your web application. So handling exceptions is a safer side for the web developer.
Do you need to specify errorpage in jsp?
Now, you don't need to specify the errorPage attribute of page directive in the jsp page.
How to handle exceptions in JSP?
There are two ways of handling exceptions in JSP. They are: 1 By errorPage and isErrorPage attributes of page directive 2 By <error-page> element in web.xml file
How many ways of handling exceptions in JSP?
There are two ways of handling exceptions in JSP. They are:
Why is it important to have a JSP page?
In order to handle exceptions using the aforementioned page directives, it is important to have a jsp page to execute the normal code, which is prone to exceptions. Also, a separate error page is to be created, which will display the exception. In case the exception occurs on the page with the exception prone code, the control will be navigated to the error page which will display the exception.
Checked Exceptions
It is usually a user error or problems which are not recognized by the developer are named as checked exceptions.
Runtime Exceptions
Runtime exceptions are the one which could have evaded by the programmer. They are overlooked at the time of compilation.
Error Exception
It is an example of the throwable class, and it is used in error pages.
What is Error?
Most of the time errors are not caused by our program these are caused by system resources. We cannot handle the errors.
Handling Exception using page directive attributes
In JSP Page Directive, there are two attributes that help in handling exceptions in JSP. They are:
Handling Exceptions Using error-page Element in web.xml File
The other way of defining the error page for each element, but in place of using the errorPage directive, the error page for each page can be specified in the web.xml file, with the help of the <error-page> element.
Example of JSP exception handling by the error-page element in web.xml file
The below example shows the usage of this technique to handle exceptions:
What is JSP page?
JSP pages provide the functionality of error page and iserror page implicit objects to deal with errors. This is called page-level exception handling.
What is a checked exception?
Checked exceptions are those exceptions that users make. It also includes exceptions that a programmer and developer can’t see. For example, a file that needs to be compiled can’t be found. The compiler y can’t ignore these exceptions at the time of compilation. Other examples can be an IO Exception or an SQL Exception.
What are the three ways to handle exceptions?
It described three ways to handle exceptions namely: direct handling, page-level exception handling and application level exception handling .
What are the errors that are ignored in compiler?
One cannot do anything about it. These include Instantiation error, Internal error, Stack Overflow etc.
Is exception handling important in JSP?
As we all know that human beings are bound to make mistakes. Same applies to the coding. While coding we might make mistakes thus exception handling is very important. In this article, we will learn about the errors in JSP and Exception handling in JSP with examples.
Can a compiler avoid an ArrayIndexOutOfBounds exception?
Unlike checked exceptions, the compiler may avoid these exceptions at the compilation time. This exception might have been avoided by the developer or programmer. Arithmetic exception, Null Pointer exception, ArrayIndexOutOfBounds exception fall under this category.
