ErrorNotes

☕ Java Errors

36 error notes

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javaintermediate

Fixing javax.validation.ConstraintViolationException in Spring Boot Persistence

javax.validation.ConstraintViolationException: Validation failed for classes [...] during persist time for groups [javax.validation.groups.Default]
javaspring-bootbean-validationhibernate
javaintermediate

Fixing EmptyResultDataAccessException in Spring Boot

org.springframework.dao.EmptyResultDataAccessException: Incorrect result size: expected 1, actual 0
spring-bootjavajpaerror-handling
javaintermediate

Fix java.lang.NoClassDefFoundError: Could not initialize class

java.lang.NoClassDefFoundError: Could not initialize class com.example.MyService
javajvmdebuggingnoclassdeffounderror
javaintermediate

Fixing Spring Security's 'Access is denied' (403 Forbidden) Errors

org.springframework.security.access.AccessDeniedException: Access is denied
javaspring-bootspring-securityauthorization
javabeginner

Fixing org.springframework.web.HttpMediaTypeNotSupportedException: Content type 'application/x-www-form-urlencoded' not supported in Spring Boot

org.springframework.web.HttpMediaTypeNotSupportedException: Content type 'application/x-www-form-urlencoded' not supported
javaspring-bootrest-apihttp
javaintermediate

Fix java.util.concurrent.RejectedExecutionException When ThreadPool Is Full or Shutdown

java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.FutureTask rejected from java.util.concurrent.ThreadPoolExecutor
javaconcurrencythreadpoolexecutor-service
javabeginner

Fix java.lang.UnsupportedClassVersionError: Class Compiled by a More Recent Java Runtime

java.lang.UnsupportedClassVersionError: com/example/MyClass has been compiled by a more recent version of the Java Runtime
javaversionjdkjre
javaintermediate

Fix java.lang.OutOfMemoryError: Direct buffer memory in Java NIO and Netty

java.lang.OutOfMemoryError: Direct buffer memory
javanionettymemory
javabeginner

Fix com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException When Deserializing JSON with Jackson

com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "fieldName" (class com.example.MyDto), not marked as ignorable
javajacksonjsonspring-boot
javaintermediate

Fix java.lang.ExceptionInInitializerError When Static Field Initialization Fails in Java

java.lang.ExceptionInInitializerError at com.example.MyClass.<clinit>(MyClass.java:15) Caused by: java.lang.NullPointerException
javastaticinitializerclassloader
javabeginner

Fix java.net.BindException: Address already in use When Starting a Java Server

java.net.BindException: Address already in use: bind
javanetworkingbindexceptionserver
javaintermediate

Fixing 'java.lang.OutOfMemoryError: GC overhead limit exceeded' in Java

java.lang.OutOfMemoryError: GC overhead limit exceeded
javajvmmemory-leakgarbage-collection
javabeginner

How to Fix java.lang.UnsupportedOperationException in Java Lists

java.lang.UnsupportedOperationException
javacollectionslistunsupportedoperationexception
javaintermediate

Fix java.lang.IllegalStateException: Duplicate Key in Collectors.toMap()

java.lang.IllegalStateException: Duplicate key (attempt to merge values key1 and key2)
javastreamsmapillegalstateexception
javaintermediate

Fix org.springframework.dao.DataIntegrityViolationException: constraint violation in Spring JPA

org.springframework.dao.DataIntegrityViolationException: could not execute statement; SQL [n/a]; constraint [users.UK_email]
javaspringjpahibernate
javabeginner

Fixing java.net.UnknownHostException: A Guide to DNS Issues in Java

java.net.UnknownHostException: api.service-provider.com
javanetworkingdnstroubleshooting
javabeginner

How to Fix java.sql.SQLException: No Suitable Driver Found

java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/db_name
javajdbcmysqlpostgresql
javaintermediate

Fixing java.lang.NoSuchMethodError: A Guide to Ending Java Dependency Conflicts

Exception in thread "main" java.lang.NoSuchMethodError: com.example.utils.StringHelper.format(Ljava/lang/String;)Ljava/lang/String;
javanosuchmethoderrordependency-conflictmaven
javabeginner

Fixing 'java.net.ConnectException: Connection refused' in Java Applications

java.net.ConnectException: Connection refused (Connection refused)
javanetworkingtroubleshootingspring-boot
javaintermediate

Fixing javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available

javax.persistence.TransactionRequiredException: No EntityManager with actual transaction available for current thread
javaspring-bootjpahibernate
javaintermediate

Fix java.lang.OutOfMemoryError: Metaspace in Java Applications

java.lang.OutOfMemoryError: Metaspace
javajvmmetaspacememory
javabeginner

How to Fix java.lang.ArrayIndexOutOfBoundsException: Index X out of bounds for length Y

java.lang.ArrayIndexOutOfBoundsException: Index X out of bounds for length Y
javaarrayindexexception
javabeginner

Fixing java.io.NotSerializableException: A Practical Guide

java.io.NotSerializableException: com.example.dto.UserDTO
javaserializationnotserializableexceptionbackend
javabeginner

Fixing NoSuchBeanDefinitionException: Why Spring Can't Find Your Bean

org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type
javaspring-bootdependency-injectiondebugging
javaintermediate

Fix java.net.SocketTimeoutException: Read timed out in Java HTTP Requests

java.net.SocketTimeoutException: Read timed out
javanetworkhttptimeout
javaintermediate

Fix java.lang.ClassCastException: class java.lang.String cannot be cast to class java.lang.Integer

java.lang.ClassCastException: class java.lang.String cannot be cast to class java.lang.Integer
javaclasscastcastinggenerics
javaintermediate

Fix javax.net.ssl.SSLHandshakeException: PKIX path building failed in Java HTTPS Calls

javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
javasslhttpscertificate
javaintermediate

Fix org.hibernate.LazyInitializationException: failed to lazily initialize a collection - no Session

org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: could not initialize proxy - no Session
javahibernatejpalazy-loading
javabeginner

Fix Spring Boot Error: Failed to configure a DataSource — 'url' attribute is not specified

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.
javaspring-bootdatasourcedatabase
javabeginner

Fix java.lang.NumberFormatException: For input string in Java

java.lang.NumberFormatException: For input string: "abc"
javanumberformatparsinginteger
javabeginner

Fix java.io.FileNotFoundException: No such file or directory in Java

java.io.FileNotFoundException: /path/to/your/file.txt (No such file or directory)
javaiofileexception
javaintermediate

Fix java.util.ConcurrentModificationException When Modifying a Collection While Iterating

java.util.ConcurrentModificationException
javacollectionconcurrencyexception
javabeginner

Fix java.lang.NullPointerException in Java

java.lang.NullPointerException
javanullpointerexceptionexception
javabeginner

Fix java.lang.StackOverflowError in Java

java.lang.StackOverflowError
javarecursionstack
javaintermediate

Fix java.lang.ClassNotFoundException: com.example.MyClass - Troubleshooting Guide

java.lang.ClassNotFoundException: com.example.MyClass
javaclasspathclassloader
javaintermediate

Fixing java.lang.OutOfMemoryError: Java heap space

java.lang.OutOfMemoryError: Java heap space
javamemoryheapjvm