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Basic syntax errors in Java are explained.

Some errors are caused by violations of the syntax of Java. Although they are easy to understand, there is no easy way to find the exact causeof such errors except by checking the code around the location of the error character by character looking for the syntax error.


The syntax of Java is very specific about the required punctuation. This error occurs, for example, if you forget a semicolonat the end of a statement or don't balance parentheses:

if (i > j        // Error, unbalanced parentheses   max = i        // Error, missing semicolonelse   max = j;

Unfortunately, this syntax error is not necessarily caught precisely at the point of the mistake so you must carefully check the preceding characters inthe line or even in a previous line in order to find the problem.

Syntax error, insert ") Statement" to complete IfStatement
Syntax error, insert ";" to complete Statement
Eclipse is more informative as to the precise syntax error encountered.

unclosed string literal

String literals must be enclosed in quotation marks. A literal is a source-code representation of a value; most literals are of primitive types like int or char , but there are also literals of type String and the literal null of any reference type. This error occurs if you fail to terminate the literal with quotation marks. Fortunately, the syntax of Javarequires that a string literal appear entirely on one line so the error message appears on the same line as the mistake. If you need a string literal that islonger than a single line, create two or more literals and concatenate them with + :

String longString =   "This is first half of a long string " +  "and this is the second half.";

Eclipse: String literal is not properly closed by a double-quote In Eclipse you can write a string literal of arbitrary length and the environment will break the string and insert the + automatically.

illegal start of expression

Most programming constructs are either statements or expressions. This error occurs when an expression is expected but not found. In Java, an assignment statement is considered to be an expression which returns a value , so errors concerning expressions also apply to assignment statements. The value of an assignment statement considered as an expressionis the value of the expression on the right-hand side that is assigned to the variable on the left-hand side. Examples:

  • An extra right parenthesis after the condition of an if -statement: if (i > j) )        // Error, extra parenthesis   max = i; Eclipse: Syntax error on token ")", delete this token The syntax of a programming language is defined in terms of tokens consisting of one or more characters. Identifiers and reserved keywords are tokens as are singlecharacters like + and sequences of characters like != . Eclipse diagnoses this as a simple syntax error and does not mention expressions.
  • Forgetting the right-hand side of an assignment statement: max = ;            // Error, missing right-hand side Eclipse: Syntax error on token "=", Expression expected after this token

Questions & Answers

How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
How can I make nanorobot?
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
how can I make nanorobot?
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Compile and runtime errors in java. OpenStax CNX. Dec 28, 2009 Download for free at http://cnx.org/content/col10913/1.2
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