try...catch<\/code> block:<\/p>\n\n\n\ntry {\n \/\/ code\n}\ncatch(Exception e) {\n \/\/ code\n}<\/code><\/pre>\n\n\n\nHere, we have placed the code that might generate an exception inside the try<\/code> block. Every try<\/code> block is followed by a catch<\/code> block.<\/p>\n\n\n\nWhen an exception occurs, it is caught by the catch<\/code> block. The catch<\/code> block cannot be used without the try<\/code> block.<\/p>\n\n\n\nExample: Exception handling using try…catch<\/h3>\n\n\n\nclass Main {\n public static void main(String[] args) {\n\n try {\n\n \/\/ code that generate exception\n int divideByZero = 5 \/ 0;\n System.out.println(\"Rest of code in try block\");\n }\n \n catch (ArithmeticException e) {\n System.out.println(\"ArithmeticException => \" + e.getMessage());\n }\n }\n}<\/code><\/pre>\n\n\n\nOutput<\/strong><\/p>\n\n\n\nArithmeticException => \/ by zero<\/samp><\/code><\/pre>\n\n\n\nIn the example, we are trying to divide a number by 0<\/code>. Here, this code generates an exception.<\/p>\n\n\n\nTo handle the exception, we have put the code, 5 \/ 0<\/code> inside the try<\/code> block. Now when an exception occurs, the rest of the code inside the try<\/code> block is skipped.<\/p>\n\n\n\nThe catch<\/code> block catches the exception and statements inside the catch block is executed.<\/p>\n\n\n\nIf none of the statements in the try<\/code> block generates an exception, the catch<\/code> block is skipped.<\/p>\n\n\n\n
\n\n\n\n2. Java finally block<\/h2>\n\n\n\n
In Java, the finally<\/code> block is always executed no matter whether there is an exception or not.<\/p>\n\n\n\nThe finally<\/code> block is optional. And, for each try<\/code> block, there can be only one finally<\/code> block.<\/p>\n\n\n\nThe basic syntax of finally<\/code> block is:<\/p>\n\n\n\ntry {\n \/\/code\n}\ncatch (ExceptionType1 e1) { \n \/\/ catch block\n}\nfinally {\n \/\/ finally block always executes\n}<\/code><\/pre>\n\n\n\nIf an exception occurs, the finally<\/code> block is executed after the try...catch<\/code> block. Otherwise, it is executed after the try block. For each try<\/code> block, there can be only one finally<\/code> block.<\/p>\n\n\n\n
\n\n\n\nExample: Java Exception Handling using finally block<\/h3>\n\n\n\nclass Main {\n public static void main(String[] args) {\n try {\n \/\/ code that generates exception\n int divideByZero = 5 \/ 0;\n }\n\n catch (ArithmeticException e) {\n System.out.println(\"ArithmeticException => \" + e.getMessage());\n }\n \n finally {\n System.out.println(\"This is the finally block\");\n }\n }\n}<\/code><\/pre>\n\n\n\nOutput<\/strong><\/p>\n\n\n\nArithmeticException => \/ by zero\nThis is the finally block<\/samp><\/code><\/pre>\n\n\n\nIn the above example, we are dividing a number by 0<\/strong> inside the try<\/code> block. Here, this code generates an ArithmeticException<\/code>.<\/p>\n\n\n\nThe exception is caught by the catch<\/code> block. And, then the finally<\/code> block is executed.<\/p>\n\n\n\nNote<\/strong>: It is a good practice to use the finally<\/code> block. It is because it can include important cleanup codes like,<\/p>\n\n\n\n- code that might be accidentally skipped by return, continue or break<\/li>
- closing a file or connection<\/li><\/ul>\n\n\n\n
\n\n\n\n3. Java throw and throws keyword<\/h2>\n\n\n\n
The Java throw<\/code> keyword is used to explicitly throw a single exception.<\/p>\n\n\n\nWhen we throw<\/code> an exception, the flow of the program moves from the try<\/code> block to the catch<\/code> block.<\/p>\n\n\n\nExample: Exception handling using Java throw<\/h3>\n\n\n\nclass Main {\n public static void divideByZero() {\n\n \/\/ throw an exception\n throw new ArithmeticException(\"Trying to divide by 0\");\n }\n\n public static void main(String[] args) {\n divideByZero();\n }\n}<\/code><\/pre>\n\n\n\nOutput<\/strong><\/p>\n\n\n\nException in thread \"main\" java.lang.ArithmeticException: Trying to divide by 0\n at Main.divideByZero(Main.java:5)\n at Main.main(Main.java:9)<\/samp><\/code><\/pre>\n\n\n\nIn the above example, we are explicitly throwing the ArithmeticException<\/code> using the throw<\/code> keyword.<\/p>\n\n\n\nSimilarly, the throws<\/code> keyword is used to declare the type of exceptions that might occur within the method. It is used in the method declaration.<\/p>\n\n\n\nExample: Java throws keyword<\/h3>\n\n\n\nimport java.io.*;\n\nclass Main {\n \/\/ declareing the type of exception\n public static void findFile() throws IOException {\n\n \/\/ code that may generate IOException\n File newFile = new File(\"test.txt\");\n FileInputStream stream = new FileInputStream(newFile);\n }\n\n public static void main(String[] args) {\n try {\n findFile();\n }\n catch (IOException e) {\n System.out.println(e);\n }\n }\n}<\/code><\/pre>\n\n\n\nOutput<\/strong><\/p>\n\n\n\njava.io.FileNotFoundException: test.txt (The system cannot find the file specified)<\/samp><\/code><\/pre>\n\n\n\nWhen we run this program, if the file test.txt<\/strong> does not exist, FileInputStream<\/code> throws a FileNotFoundException<\/code> which extends the IOException<\/code> class.<\/p>\n\n\n\nThe findFile()<\/code> method specifies that an IOException<\/code> can be thrown. The main()<\/code> method calls this method and handles the exception if it is thrown.<\/p>\n\n\n\nIf a method does not handle exceptions, the type of exceptions that may occur within it must be specified in the throws<\/code> clause.<\/p>\n","protected":false},"excerpt":{"rendered":"In the tutorial, we will learn about different approaches of exception handling in Java with the help of examples. In the last tutorial, we learned about\u00a0Java exceptions. We know that exceptions abnormally terminate the execution of a program. This is why it is important to handle exceptions. Here’s a list of different approaches to handle […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[569],"tags":[],"_links":{"self":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1243"}],"collection":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/comments?post=1243"}],"version-history":[{"count":0,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/posts\/1243\/revisions"}],"wp:attachment":[{"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/media?parent=1243"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/categories?post=1243"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/mudassirbackup.infinitycodestudio.com\/index.php\/wp-json\/wp\/v2\/tags?post=1243"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}