Basic Java Debugging

This instruction guide covers a basic step by step check for Java error handling. This guide does not provide any assistance in setting up java programming software and expects that you have already accomplished this task ahead of time. For the best use of this guide, come back to it whenever an error occurs that you are uncertain about and check through the 8 common possibility’s until you are either met with a solution or reach the end. Keep in mind, these examples are all relatively basic and are meant for beginner support.

Before you begin checking through each possible solution, take a look at the error that Java is notifying you with. Each step will begin by showcasing the error that it is associated with.

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Step 1: ​“Syntax Error, Insert “;” to Complete BlockStatements”.

This is the most basic of Syntax errors, it simply means you forgot a semicolon at the end of your statement. All declaration and expression statements will end with a semicolon. In some other instances such as with if, else, and for statements you will not need to place the semicolon.

Step 2: “cannot Be Resolved to a Variable”, or “insert VariableDeclarators”

This Syntax error occurs when you are attempting to use a variable without having created it first or provided it a data type. Simply add the data type that is associated with your variable, examples could be “int”, “boolean”, “char”, and “double”.

Step 3: “insert “}” to Complete ClassBody"

Our next Syntax error has to do with curly bracket. You will normally see the error occur when you’ve missed either one or both curly brackets. If you are missing both you will see the error, “insert “ClassBody” to complete ClassDeclaration". If only one is missing you will either see the error, “insert “}” to complete ClassBody" or “{ expected after this token”. The errors will normally occur on the line were the curly bracket can be placed to provide a fix.

Step 4: Infinite Loop

We now look at a case where an error will most likely not be provided by the Java client. This occurs when you have a loop such as a while loop or a for loop that cycles infinitely. There is no simple answer to the solution because each person’s code will vary but trying to add a manual supplementary limit within the code should be the primary goal. After that attempt to figure out why your code was unable to meet your loops break condition?

Step 5: “cannot Be Resolved to a Type”

This Syntax error has to do with imports. Whenever we want to use an API from another class, we must import that class to the current one. A common occurrence for this is the use of the Scanner function, in order to use it you must import the “java.util.Scanner” class. Keep in mind this is only an example.

Step 6: “The Method “” Is Undefined for the Type”

This Syntax error occurs when we forget the class name during a method call. The primary example for this would be whenever we attempt to print. If you’re someone who’s coming off of a language that uses a simple print() function then this can occur frequently. You will instead want to use System.out.print() or System.out.println(). This will always occur during method calls.

Step 7: “string Literal Is Not Properly Closed by a Double-quote”

This Syntax occurs when we are using Strings. The problem has to do with an open but not closed String. It is always marked on the line where it occurs and is fixed by placing that second double quotation. As a side note, if you attempt to use single quotations for Strings that will also result in an error “invalid character constant”.

Step 8: “return Type for the Method Is Missing”

The last Syntax worth mentioning is the method return type and missing return. The “return type for the method is missing” occurs when you have a method that attempts to return something while missing the specification of that type in the method signature. The error will occur in the signature and is usually a very fast solve. When it comes to the “method must return a result of type” error you just need to make sure you return something with that type.

Step 9: Extra Assistance

If you were unable to find a fix for your error, then consider attempting one of these following options. Copy Java’s note on the error that occurred and attempt to find a solution by pasting it into some web search. Search for some more advanced or explicit Java error handling guides. Lastly, if none of these options helped and you have the time to spare, attempt to post your question on a support forum such as Stackoverflow. You will commonly get a response fix with an explanation as to why the error occurred in the first place.

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    seamster

    7 months ago

    Thank you for sharing these tips. Welcome to the site! : )