JAVA是一種面向對象的編程語言，擁有眾多的關鍵字和系統(tǒng)類，下面就讓我們一起來了解一下。

關鍵字：

abstract
continue
for
new
switch
assert
default
goto
package
synchronized
boolean
do
if
private
this
break
double
implements
protected
throw
byte
else
import
public
throws
case
enum
instanceof
return
transient
catch
extends
int
short
try
char
final
interface
static
void
class
finally
long
strictfp
volatile
const
float
native
super
while

系統(tǒng)類：

Object
String
StringBuilder
StringBuffer
Math
Boolean
Character
Number
Byte
Short
Integer
Long
Float
Double
BigInteger
BigDecimal
Enum
Date
Calendar
TimeZone
SimpleTimeZone
DateFormat
SimpleDateFormat
CharArrayReader
CharArrayWriter
InputStream
ByteArrayInputStream
FileInputStream
FilterInputStream
DataInputStream
PushbackInputStream
ObjectInputStream
BufferedInputStream
InputStreamReader
StringReader
OutputStream
ByteArrayOutputStream
FileOutputStream
FilterOutputStream
DataOutputStream
PrintStream
ObjectOutputStream
BufferedOutputStream
OutputStreamWriter
StringWriter
PrintWriter
Reader
BufferedReader
InputStreamReader
StringReader
FileReader
StringWriter
Writer
BufferedWriter
OutputStreamWriter
PrintWriter
FileWriter
Date
Format
InputStream
OutputStream
RandomAccessFile
Throwable
Exception
RuntimeException
Class
ClassLoader
System
Runtime
Process
Thread
ThreadGroup
InterruptedException
ArithmeticException
NullPointerException
IllegalArgumentException
IndexOutOfBoundsException
ArrayIndexOutOfBoundsException
SecurityException
OutOfMemoryError
StackOverflowError

以上是JAVA中的關鍵字和系統(tǒng)類，掌握它們將會為我們的編程工作提供很大的幫助。