Common Java Errors and How to Fix Them
Browse all documented Java errors with detailed explanations, root causes, and step-by-step fixes.
java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.Threa
This error occurs when a task is submitted to an executor service that is shutting down or has been terminated.…
Cannot find symbol: class Scanner on line 5
This error occurs when Java cannot find a class, method, or variable that is being used in the code. It is often caused …
java.sql.SQLException: Cannot execute query while there is an open result set
This error occurs when you try to execute a new query while a previous query's result set is still open, preventing the …
Parameter index out of range: 2, query was: SELECT * FROM users WHERE username =
This error occurs when the number of parameters in a SQL query does not match the number of placeholders (represented by…
Syntax error on token "return", { expected after this token
This error occurs when Java encounters syntax that does not conform to the language's rules. In this case, Java is expec…
SQLSyntaxErrorException: No value specified for parameter '#1'
This error occurs when a prepared statement in Java is executed with a parameter that has not been defined or initialize…
Syntax error on token 'int', delete this token
This error occurs when the compiler encounters unexpected syntax in the code, making it difficult to parse and compile.…
java: cannot find symbol symbol: class Scanner location: class Main
This error occurs when the Java compiler cannot find a class, method, or variable that is used in the code. In this case…
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating
This error occurs when Spring cannot find or autowire a required bean, often due to a missing or incorrect dependency co…
illegal start of type: if at line 15 column 1
This error occurs when the Java compiler encounters a syntax that is not allowed in the Java programming language.…
Cannot execute query with parameter types [java.util.Date, java.lang.String] in
This error occurs when trying to execute a prepared statement with parameters of unsupported types. The JDBC driver does…
SQLSyntaxErrorException: ORA-00933: SQL command not properly ended
This error occurs when the SQL query is not properly formatted or ended, resulting in a syntax error. This can happen wh…
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