<< Chapter < Page Chapter >> Page >
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.

...expected

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.

Eclipse:
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

what is mutation
Janga Reply
what is a cell
Sifune Reply
how is urine form
Sifune
what is antagonism?
mahase Reply
classification of plants, gymnosperm features.
Linsy Reply
what is the features of gymnosperm
Linsy
how many types of solid did we have
Samuel Reply
what is an ionic bond
Samuel
What is Atoms
Daprince Reply
what is fallopian tube
Merolyn
what is bladder
Merolyn
what's bulbourethral gland
Eduek Reply
urine is formed in the nephron of the renal medulla in the kidney. It starts from filtration, then selective reabsorption and finally secretion
onuoha Reply
State the evolution relation and relevance between endoplasmic reticulum and cytoskeleton as it relates to cell.
Jeremiah
what is heart
Konadu Reply
how is urine formed in human
Konadu
how is urine formed in human
Rahma
what is the diference between a cavity and a canal
Pelagie Reply
what is the causative agent of malaria
Diamond
malaria is caused by an insect called mosquito.
Naomi
Malaria is cause by female anopheles mosquito
Isaac
Malaria is caused by plasmodium Female anopheles mosquitoe is d carrier
Olalekan
a canal is more needed in a root but a cavity is a bad effect
Commander
what are pathogens
Don Reply
In biology, a pathogen (Greek: πάθος pathos "suffering", "passion" and -γενής -genēs "producer of") in the oldest and broadest sense, is anything that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ. The term pathogen came into use in the 1880s.[1][2
Zainab
A virus
Commander
Definition of respiration
Muhsin Reply
respiration is the process in which we breath in oxygen and breath out carbon dioxide
Achor
how are lungs work
Commander
where does digestion begins
Achiri Reply
in the mouth
EZEKIEL
what are the functions of follicle stimulating harmones?
Rashima Reply
stimulates the follicle to release the mature ovum into the oviduct
Davonte
what are the functions of Endocrine and pituitary gland
Chinaza
endocrine secrete hormone and regulate body process
Achor
while pituitary gland is an example of endocrine system and it's found in the Brain
Achor
what's biology?
Egbodo Reply
Biology is the study of living organisms, divided into many specialized field that cover their morphology, physiology,anatomy, behaviour,origin and distribution.
Lisah
biology is the study of life.
Alfreda
Biology is the study of how living organisms live and survive in a specific environment
Sifune
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Compile and runtime errors in java. OpenStax CNX. Dec 28, 2009 Download for free at http://cnx.org/content/col10913/1.2
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Compile and runtime errors in java' conversation and receive update notifications?

Ask