{"id":1944,"date":"2018-05-04T15:16:00","date_gmt":"2018-05-04T15:16:00","guid":{"rendered":"https:\/\/www.testingdocs.com\/questions\/?p=1944"},"modified":"2024-08-09T09:10:08","modified_gmt":"2024-08-09T09:10:08","slug":"how-to-fix-java-util-inputmismatchexception","status":"publish","type":"post","link":"https:\/\/www.testingdocs.com\/questions\/how-to-fix-java-util-inputmismatchexception\/","title":{"rendered":"How to fix java.util.InputMismatchException"},"content":{"rendered":"

How to fix java.util.InputMismatchException<\/h2>\r\n

InputMismatchException is a common exception when we work with Java programs that prompts and take input from the user. As the exception name indicates the input doesn’t match with the program expectations for the data.<\/p>\r\n

The root cause<\/h3>\r\n

We get this error when the user enters the input that mismatches with the expected datatype of the input variable in the program. Let’s say the program expects a double<\/strong> value and the user enters a String<\/strong> value.<\/p>\r\n

 <\/p>\r\n

\"InputMismatchException\"<\/p>\r\n

\u00a0<\/h3>\r\n

Stack Trace of InputMismatchException<\/h3>\r\n
Exception in thread \"main\" java.util.InputMismatchException\r\nat java.base\/java.util.Scanner.throwFor(Scanner.java:939)\r\nat java.base\/java.util.Scanner.next(Scanner.java:1594)\r\nat java.base\/java.util.Scanner.nextInt(Scanner.java:2258)\r\nat java.base\/java.util.Scanner.nextInt(Scanner.java:2212)\r\nat Demo.main(Demo.java:16)<\/pre>\r\n
 <\/p>\r\n
Scanner class throws this exception.<\/p>\r\n
\"\"<\/p>\r\n
Screenshot<\/h3>\r\n
Fix is to handle the exception and let the user know about the error in the input. In the below example, the code is wrapped with a try – catch<\/strong> block. So, if the code throws the exception the catch handler is invoked to notify the user with a user- friendly message.\u00a0<\/p>\r\n
If the user enters a valid data for the radius then the catch block would not be executed. This is because the code doesn’t throw the exception when the input is valid.<\/p>\r\n

Java Listing<\/h3>\r\n
import java.util.InputMismatchException;\r\nimport java.util.Scanner;\r\n\/**************************************************\r\n * Demo.java\r\n * @program   \t: \r\n * @web        \t: www.TestingDocs.com\r\n * @author      :  \r\n * @version     : 1.0\r\n **************************************************\/\r\npublic class Demo {\r\n  \/\/main\r\n  public static void main(String[] args) {\r\n    Scanner keyboard = new Scanner(System.in);\r\n    double radius=0.0;\r\n    double areaCircle=0.0;\r\n\r\n    try {\r\n      System.out.println(\"Enter Radius := \");\r\n      radius = keyboard.nextDouble();\r\n      areaCircle = Math.PI*radius*radius;\r\n      System.out.println(\"Area of Circle = \"+ areaCircle);\r\n      keyboard.close();\r\n    }catch(InputMismatchException ime) {\r\n      System.out.println(\"Please enter valid number for radius\");\r\n    }\r\n  } \/\/ end main\r\n} \/\/ end Demo<\/pre>\r\n
 <\/p>\r\n
Sample run output<\/strong><\/p>\r\n
Enter Radius := 
zzz
Please enter valid number for radius<\/p>\r\n
The string ‘zzz’ is invalid data for radius with double<\/strong> datatype. The code in the try block throws an exception. The catch block handle it and displays a message to the user.\u00a0<\/p>\r\n
—<\/p>\r\n
Java Tutorial on this website:<\/p>\r\n
https:\/\/www.testingdocs.com\/java-tutorial\/<\/a><\/p>\r\n

For more information on Java, visit the official website :<\/p>\r\n
https:\/\/www.oracle.com\/in\/java\/<\/a><\/p>\r\n","protected":false},"excerpt":{"rendered":"
How to fix java.util.InputMismatchException InputMismatchException is a common exception when we work with Java programs that prompts and take input from the user. As the exception name indicates the input doesn’t match with the program expectations for the data. The root cause We get this error when the user enters the input that mismatches with […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[18],"tags":[],"class_list":["post-1944","post","type-post","status-publish","format-standard","hentry","category-java-programs","has-post-title","has-post-date","has-post-category","has-post-tag","has-post-comment","has-post-author",""],"_links":{"self":[{"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/posts\/1944","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/comments?post=1944"}],"version-history":[{"count":10,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/posts\/1944\/revisions"}],"predecessor-version":[{"id":23861,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/posts\/1944\/revisions\/23861"}],"wp:attachment":[{"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/media?parent=1944"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/categories?post=1944"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/tags?post=1944"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}