Compile Time Error Java
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Run Time Error Java
Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it runtime error java only takes a minute: Sign up Compile time vs run time errors [duplicate] up vote 3 down vote favorite 1 Possible Duplicate: Runtime vs Compile time How should I know whether a specific line of code in Java may compile time errors in c++ throw a compile time or run-time error? Assuming that the specific line of code anyway throws and error. java runtime compile-time share|improve this question edited May 6 '13 at 22:09 Undo♦ 18.4k157399 asked Oct 14 '12 at 12:58 uml 4503921 marked as duplicate by home, Junuxx, Denys Séguret, S.L. Barth, dSquared Oct 14 '12 at 14:35 This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new
Compile Time Error And Runtime Error In C
question. 1 stackoverflow.com/questions/846103/runtime-vs-compile-time –Matt Whipple Oct 14 '12 at 13:01 add a comment| 5 Answers 5 active oldest votes up vote 11 down vote accepted In Eclipse, compile time errors will be underlined in red. A compile time error is an error that is detected by the compiler. Common causes for compile time errors include: Syntax errors such as missing semi-colon or use of a reserved keyword (such as 'class'). When you try and access a variable that is not in scope. When you declare multiple objects with the same name. If the compiler detects any errors during compilation it will fail to build a new assembly (or class file in Java). Even if your code has no compile time errors, errors can still occur on run-time. Errors such as 'logic errors' and 'runtime errors'. A good example of a runtime error is as followed: Pretend you're going to store an item in an array at index 5 but the array's size is only 4. The compiler won't detect an error here because it understands that the array size is subject to change but on run-time you'll be thrown an exception. To detect which line exactly a run-time error occurs on you can use a combination of break points in Eclipse and proper exception handling. share|improve this answer answered Oct 14 '12 at 13:08 Caster Troy 1,355832 add a comment| up vote 6 down vote To s
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Error Of Intent
it a compiler error and when is it a runtime exception? up vote 2 down vote favorite I am currently studying for the SCJP certification using the Sierra and Bates Study Guide and in many of the self tests (mock exam questions) I http://stackoverflow.com/questions/12882448/compile-time-vs-run-time-errors keep running into the same problem - I can't tell whether a particular error will be at runtime (an exception) or at compile (compile error). I know this is a bit of a vague question and that it might not be possible to answer but, how can I tell if an error will be found at compile or at runtime? Would you be able to send me some website links that might be able to help me? java exception compilation scjp share|improve this question edited May http://stackoverflow.com/questions/3179504/java-when-is-it-a-compiler-error-and-when-is-it-a-runtime-exception 17 '11 at 12:40 Bill the Lizard 222k138447737 asked Jul 5 '10 at 12:40 Michael 13113 1 If you posted some concrete question(s) (and your own reasoning about the possible answers), we could help better. –Péter Török Jul 5 '10 at 12:44 I'm not sure if this "human compiler" skill is all that useful, honestly, beyond some basic working understanding of the language and the API. It's pretty much guaranteed that there will always be a Java snippet that even James Gosling can't tell if it will compile and/or what it's actually doing. –polygenelubricants Jul 5 '10 at 13:04 The problem is that for the SCJP, you really are required to be able to state whether the error (if any) will be evoked at runtime or at compile –Michael Jul 5 '10 at 13:08 @Peter Torok I'm sorry my question wasn't that clear but it was a bit hard to explain. If you read my comment on Andreas_D's answer it might make things a little bit more clear I suppose. –Michael Jul 5 '10 at 13:10 add a comment| 2 Answers 2 active oldest votes up vote 6 down vote accepted Compile time error - the java compiler can't compile the code, often because of syntax errors. Typical candidates: missing brackets missing semicolons access to private fields in other classes missing classes on the classpath (at compile time) Runtime error - the code did compile, can be executed but crashes at some point, like you have a division by zero. us
when you include disallowed characters in your code (e.g. int #people = 10;). Syntactical: These occur when your code is "out of order" (e.g. for (int i=0; i++; i<10)). Semantic: These occur when the meaning of your code is unclear (e.g. two variables with the same https://www.student.cs.uwaterloo.ca/~cs133/Resources/Java/Debugging/compile.shtml name). Note that the exact wording of these errors may vary, depending on which development environment https://www.quora.com/What-is-the-difference-between-runtime-and-compile-time you are using. Errors described on this page (click to jump to that error): Cannot return a value from a method of type void 'Class' or 'interface' expected Class should be delcared abstract; it does not define... Else without if Expected: ;, {, }, (, or ) Identifier expected / Illegal character Incompatible types / Inconvertible types (cannot cast) Method does not return a time error value / Missing return statement Method not found Not a statement Return type required Unreachable statement Variable already defined Variable not declared Cannot return a value from a method of type void When a method is declared as having a return type of void, it cannot contain any return statements which return a value (it can, however, contain a return statement by itself, which will simply end the execution of the method). This problem is usually caused by accidentally making compile time error a method be of type void when it shouldn't be or by accidentally including a return statement where there shouldn't be one. Example 1: Incorrect Code Example 1: Fixed Code This method has a return type of void and so it may not return any values. We change the return type of this method in order to fix the problem. 01 public void getName() 02 { return this.name; 03 } 01 public String getName() 02 { return this.name; 03 } 'Class' or 'interface' expected This error will most likely be caused when you omit the keyword class or interface, as seen in the example below. Example 1: Incorrect Code Example 1: Fixed Code Here, we do not have either keyword present. We add in class or interface, depending on our intentions within the program. 01 public Test 02 { 03 public void someMethod() 04 { System.out.println("Hello, world!"); 05 } 06 } 01 public class Test 02 { 03 public void someMethod() 04 { System.out.println("Hello, world!"); 05 } 06 } -- OR -- 01 public interface Test 02 { 03 public void someMethod(); 04 } Class should be delcared abstract; it does not define... This error arises when implementing an interface. Recall that when you say implements SomeInterface for a certain class, you guarantee that you have written all of the methods specified within that interface. If you are missing at least one of the methods which is listed in the i
runtime and compile time?UpdateCancelAnswer Wiki6 Answers Nitin Abhishek, hobbyist, RC aircraft modellerWritten 103w agoAlmost all computer programs written are in high level languages, which is a little closer to English than a sequence of 0's and 1's that is the machine language, so us humans have an easier time understanding and working with the code. To convert this program code into an executable file that can be read and executed by a machine, we use a Compiler.Now when you just use the terms runtime and compile time, the first thing that comes to mind are the compile time errors and runtime errors: Compile time errors: When we feed a bunch of text to the compiler to convert it to machine code.What can go wrong at compile time: Syntax errorsTypechecking errors(Rarely) compiler crashesIf the compiler succeeds, what do we know? The program was well formed---a meaningful program in whatever language.It's possible to start running the program as it's in a machine readable form. (The program might fail immediately, but at least we can try.)What are the inputs and outputs? Input was the program being compiled, plus any header files, interfaces, libraries, or other voodoo that it needed to import in order to get compiled.Output is hopefully assembly code or relocatable object code or even an executable program. Or if something goes wrong, output is a bunch of error messages.Runtime errors: What can go wrong are run-time errors:Division by zeroDeferencing a null pointerRunning out of memoryAlso there can be errors that are detected by the program itself:Trying to open a file that isn't thereTrying find a web page and discovering that an alleged URL is not well formedIf run-time succeeds, the program finishes (or keeps going) without crashing.Another scenario where the two terms can be used is in reference to when exactly is the source code compiled or converted to machine code: once just after the code is written i.e. compiled programs, or every time just before the program needs to run, i.e. interpreted programs, or compiled at runtime: In a compiled program (ex