Troubleshooting Java Programming Error Types

June 19, 2020 by Beau Ranken



In the past few days, some of our users have received error messages with types of Java programming errors. This problem can occur for several reasons. We will discuss it now. There are three types of errors: syntax errors, runtime errors, and logical errors. These are errors when the compiler detects that something is wrong with your program, and you cannot even start it.

java programming error types


What is a Java error?

A bug is a Throwable subclass that points to serious issues that should not be resolved with reasonable use. Most of these errors are abnormal. A ThreadDeath error is a “normal” condition, but it is also a subclass of Error, since most applications should not try to catch it.


September 2020 Update:





There Are Three Types Of Errors In Java

Compilation Error:

These errors are errors that prevent compilation of the code due to a syntax error, for example, for example, due to the absence of a semicolon at the end of the statement or due to the absence of parentheses, the class was not found, etc. These errors are recognized by the compiler Java and display an error during compilation on the screen.

Runtime Error:

These errors are errors that occur during program execution. Runtime errors are not recognized by the Java compiler. This is the JVM that it recognizes at runtime.

Logical Errors:

These errors are due to errors made by the programmer. It is not recognized by either the compiler or the JVM. Errors can occur due to incorrect ideas or concepts that the programmer uses when coding.


An exception is a runtime error that can be handled or prevented and occurs at runtime. Some exceptions may be recognized by the Java compiler at compile time and are called validation These exceptions, while those recognized by the JVM at run time, are called unchecked exceptions.

Many types of errors can occur when developing Java software, but most of them can be prevented. We've compiled the 50 most common bugs in Java software with code samples and tutorials to help you avoid common coding issues.

Additional tips and tricks for writing the best Java programs can be found in our complete Java developer guide, which has everything you need to update your Java game - from tools to the best websites and blogs. YouTube - Twitter feeds and influencers, LinkedIn groups, podcasts, must-see events, etc.

If you are working with .NET, you should also read our guide to the 50 most common .NET software errors and learn how to avoid them. However, if your current problems are related to Java, read on to find out more about common problems and how to solve them.nyah.

Compiler Error

Compiler error messages are generated when Java software code is run through the compiler. It is important to note that the compiler can print many error messages for one error. So fix the first mistake and recompile it. This can solve many problems.

1. "... Expected"

2. "Unclosed String Literal"

The "String literal is not closed" error message is generated when the string literal ends without quotes and the message appears on the same line as the error. (@DreamInCode) A literal is the source code of a value.

3. "Wrong Start Of Expression"

There are many causes for the "Wrong Start of Expression" error. This is one of the least useful error messages. Some developers say this is due to bad code.

Typically, expressions are created to create a new value or to assign a value to a variable. The compiler expects to find an expression and cannot find it, because the syntax is not as expected. (@StackOverflow) Error in thesestructures.

4. "Icon Not Found"

This is a very common problem, because all identifiers must be declared in Java before they can be used. When the code compiles, the compiler does not understand what the identifier means.

5. "Public Class XXX Must Be In The File"

The message "open class XXX must be in the file" is displayed if the class XXX and the file name of the Java program do not match. Code compiles only if the class and Java file are identical. (@coderanch)

6. "Incompatible Types"

"Incompatible types" is a logical error that occurs when an assignment operator tries to bind a variable to a type expression. This often happens when the code tries to insert a text string into an integer or vice versa. This is not a Java syntax error. (@StackOverflow)

7. "Invalid Method Declaration; Required Return Type"

8. "The Method Of Class Cannot Be Applied To Certain Types"

This Java software error message is one of the most useful error messages. This explains how the signature of the call method Incorrect parameters.

The called method expects certain arguments that are defined in the method declaration. Check the method declaration and call it carefully to make sure it is compatible

This discussion shows how a Java software error message identifies incompatibilities caused by arguments in a method declaration and in a method call. (@StackOverflow)

9. "Missing Return Instruction"

The message “Missing return instruction” is displayed if the method does not have a return instruction. Any method that returns a value (an invalid type) must have an instruction that literally returns that value so that it can be called outside the method.

10. "Possible Loss Of Accuracy"

"Possible loss of accuracy" occurs when a variable receives more information than it can contain. In this case, coins are thrown away. If this is correct, the code should explicitly declare the variable as a new type.

11. “End Of File Reached During Parsing”

This error message usually appears in Java if The program does not have a closing bracket ("}"). Sometimes this can be quickly fixed by placing it at the end of the code.

12. "Ad Unavailable"

"Instruction unavailable" occurs when the instruction is written in a place that prevents execution. This is usually done after the break or return statement.

The error is often resolved by simply moving the return statement. Read the discussion on how to fix an unavailable Java software error. (@StackOverflow)

13. "Perhaps The Variable Is Not Initialized"

This occurs when a local variable declared in a method has not been initialized. This can happen if a variable without an initial value is part of an if statement.

14. "The Operator .. Cannot Be Applied To "

This often happens when Java code tries to use a type string in a calculation. To solve this problem, the string must be converted to an integer or a floating point number.

Read this example of how non-numeric types caused a Java software error warning that the statement could not be applied totype. (@StackOverflow)

15. "Non-convertible Types"

16. "Missing Return Value"

17. "It Is Impossible To Return A Value From A Method Whose Result Type Is Invalid"

This is often solved by changing the method signature to match the type in the return statement. In this case, void instances can be replaced with int:

18. “Non-static Variable. ,, Cannot Be Referenced From A Static Context "

To correct non-static variables. ,, cannot be referenced from a static context ", two things can be done:

19. "Non-static Method. ,, Cannot Be Referenced From A Static Context "

This problem occurs when Java code tries to call a non-static method in a non-static class. Example: the following code:

To call a non-static method from a static method, you must declare an instance of the class that calls the non-static method.

20. "(table) Not Initialized"

You will receive the message “(Array) not initialized” if the array was declared but not initialized. Tables have a fixed length, so each table must have an initiallysed to the desired length.

Runtime Exceptions

21. "ArrayIndexOutOfBoundsException"

This is a run-time error message that appears when code tries to access an index of an array that is not in the values. The following code will throw this exception:

Array indices start from zero and end one less than the length of the array. This is often solved with "<" instead of "<=" when setting the limits of the array index.

22. "StringIndexOutOfBoundsException"

This is a problem that occurs when the code tries to access the part of the chain that is outside of it. This usually happens when the code tries to create a substring of a string that does not match the given parameters. Here is an example (@javacodegeeks):

Like array indexes, string indexes start at zero. When indexing a string, the last character is one less than the length of the string. The Java software error message “StringIndexOutOfBoundsException” usually means that the index is trying to access non-existent characters.

23. "NullPointerException"

"NullPointerException" occurswhen the program tries to use a reference to an object that is not assigned a value (@geeksforgeeks).

24. "NoClassDefFoundError"




What are the types of exception?

There are two main types of exceptions: enabled and disabled, where errors are considered an unchecked exception. The solar microsystem indicates that there are three types of exceptions: a checked exception. Exception is disabled.

Types of exception handling:
  • Class not found, exception.
  • IOException.
  • Exclusion from execution.





types of error in java in hindi




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