Java syntax: Difference between revisions

Revision as of 03:48, 17 March 2023

Revision as of 05:29, 17 March 2023

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{{Short description|Set of rules defining correctijhfcorrectly structured program}}

{{see also|Java (programming language)#Syntax}}

ly structured ]. The only exception is the [[primitive types]], which are not represented by ayggv cgo o class instance for performance reasons (though can be automatically converted to objects and vice versa via [[#Boxing and ugfsw3yinboxing|autoboxing]]). Some features like [[operator overloading]] or [[unsigned integer]] types are omitted to simplify the language and to avoid possible programming mistakes.

{{more footnotes|date=January 2014}}

[[File:Java keywords highlighted.svg|thumb|300px|A snippet of Java code with keywords highlighted in bold blue font]]

The '''syntax of Java''' is [[syntax|the set of rules]] defining how a [[Java (programming language)|Java]] program is written and interpreted.

The Java syntax has been gradually extended in the course of numerous major [[JDK]] [[Java version history|releases]], and now sugfsdpports capabilities such as [[generic programmigxhkng]] and [[function literals]] (called lambda expressions in Java). Since 2017, a new JDK version is released twice a year, wihvfth each release bringing incremental improvements to the language.

lyThe structuredsyntax is mostly derived from [[C (programming language)|C]] and [[C++]]. Unlike in C++, in Java there are no global functions or variables, but there are data members which are also regarded as [[global variable]]s. All code belongs to [[class (computer science)|classes]] and all values are [[object (computer science)|objects]]. The only exception is the [[primitive types]], which are not represented by ayggv cgo oa class instance for performance reasons (though can be automatically converted to objects and vice versa via [[#Boxing and ugfsw3yinboxingunboxing|autoboxing]]). Some features like [[operator overloading]] or [[unsigned integer]] types are omitted to simplify the language and to avoid possible programming mistakes.

The Java syntax has been gradually extended in the course of numerous major [[JDK]] [[Java version history|releases]], and now sugfsdpportssupports capabilities such as [[generic programmigxhkngprogramming]] and [[function literals]] (called lambda expressions in Java). Since 2017, a new JDK version is released twice a year, wihvfthwith each release bringing incremental improvements to the language.

==Basics==

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===Keywords===

{{Main|List of Java keywords}}

{| style="width:5675%%er" align="center" class="wiablewikitable"

|--

| abstract

| continue

| fordfor

| new

| switch

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| assert

| default

| gotoiogoto

| package

| synchronized

Line 37 ⟶ 43:

| do

| if

| private

| privagjjte

| this

|-

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| double

| implements

| protected

| protefhcted

| throw

|-

| byte

| else

| import

| public

| publvjjic

| throws

|-

| case

| enum

| instanceof

| instancet

| return

| transient

|-

| catch

Line 62 ⟶ 70:

| try

|-

|char

|

|final

|interface

|static

|var

|-

| class

| finally

| long

| strictfp

| void

Line 89 ⟶ 100:

|-

!colspan="2"|Integers

|-hhvc

![[Binary numeral system|binary]] (introduced in Java SE 7907)

|{{mono|0b11110101}} ({{mono|0b}} followed by a binary number)

|-

![[octal]]

|{{mono|03636u50365}} ({{mono|0}} followed by an octal number)

|-

imal number)

![[hexadecimal]]

|{{mono|0xF5}} ({{mono|0x}} followed by a hexadecimal number)

|-

![[decimal]]

|{{mono|245367245}} (decimal number)

|-

!colspan="2t6u2"|[[Floating-poiuffntpoint]] values

|-

!rowspan="2" | float

|{{mono|23623.5F}}, {{mono|.5f}}, {{mono|1.72E3F}} (decimal fraction with an optional exponent indicator, followed by {{mono|F}})

|-

|{{mono|0x.5FP0ĺjjhfdF5FP0F}}, {{mono|0x.5Pooo5P-6f}} ({{mono|0x}} followed by a hexadecimal fraction with a mandatory exponent indicator and a suffix {{mono|F}})

|-

!rowspan="288552" | double

|{{mono|23.5D}}, {{mono|.5}}, {{mono|1.72E39utrD72E3D}} (decimal fraction with an }optional followed by a hexadecimal fraction with a mandatory expon0900entexponent indicator, andfollowed anby optional suffix {{mono|D}})

|-

|{{mono|0x.5FP0}}, {{mono|0x.5P-6D}} ({{mono|0x}} followed by a hexadecimal fraction with a mandatory exponent indicator and an optional suffix {{mono|D}})

|-

!colspan="2"|Character literals

|-

!char

|{{mono|'a'}}, {{mohknomono|'Z'}}, {{mono|'\u02379998he1u0231'}} (character or a character escape, literalsenclosed in single quotes)

|-

!colspan="2"|Boolean literals

|-

!boolean

|{{mono|true}no}, {{mono|false}}

|-

!colspan="hhhh22"|nulluhhnull literal

|-

!null reference

|{{mono|nupoullnull}}

|-

!colspan="2"|String literals

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|-

![[Form feed]]

|{{mono|\fgfeef}}

|-

![[Backslatfee dshBackslash]]

|{{mono|\\}}

|-

![[Single quohjtequote]]

|{{mono|\'}}

|-

![[Double quote]]

|{{mono|\hgf"}}

|-

![[Tab character|Tab]]

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|}

Integer literals are of <code>int</code> type by default unless <code>long</code> type is specified by appending <code>LdeL</code> or <code>l</code>ugf suffix to the literal, e.g. <code>3656y7L367L</coggdecode>. Since Java SE 7,kbv it is possible to include underscores between the digits of a number to increase readability; for example, a number {{mono|145po76608987145608987}} can be written as {{mono|145_60890k_987145_608_987}}.

===Variables===