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Class System is class of
java.lang
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class System encapsulates...
... several aspects of the run-time environment
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System contains predefined stream variables:
in, out, and err
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in, out, and err declared as:
This means:
- public, final, and static within System
- This means they can be used by any other part of your program and without reference to a specific System object.
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System.out refers to the...
Which is by default ...
- ... standard output stream
- ... console
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System.in refers to the ...
Which is by default ...
- ... standard input stream
- ... keyboard
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System.err refers to the ...
Which is by default ...
- ... standard error stream
- ... console
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System.in is an object of type ...
... InputStream
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System.out is an object of type
... PrintStream
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System.err is an object of type ...
... PrintStream
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InputStream is a class of ...
java.io.InputStream
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PrintStreamis a class of ...
java.io.OutputStream.FilterOutputStream.PrintStream
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System.in is an instance of ...
- ... InputStream,
- so automatically have access to the methods defined by InputStream
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System.out is instance of ...
- PrintStream,
- so automatically have access to the methods defined by PrintStream
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System.err is instance of ...
- PrintStream,
- so automatically have access to the methods defined by PrintStream
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Methods of java.io.InputStream (9)
- 1 - int available()
- 2 - void close()
- 3 - void mark(int readlimit)
- 4 - boolean markSupported()
- 5 - abstract int read()
- 6 - int read(byte[ ] b)
- 7 - int read(byte[ ] b, int off, int len)
- 8 - void reset()
- 9 - long skip(long n)
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Returns number of bytes currently available for reading
- int available()
- java.io.InputStream
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int available()
- java.io.InputStream
- Returns number of bytes currently available for reading
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Closes this input source
- void close()
- java.io.InputStream
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void close()
- java.io.InputStream
- Closes this input source
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Places a marks at the current point in the input stream that will remain valid until "readlimit" bytes are read
- void mark(int readlimit)
- java.io.InputStream
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void mark(int readlimit)
- java.io.InputStream
- Places a marks at the current point in the input stream that will remain valid until "readlimit" bytes are read
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Returns "true" if this input stream supports the mark and reset methods
- boolean markSupported()
- java.io.InputStream
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boolean markSupported()
- java.io.InputStream
- Returns "true" if this input stream supports the mark and reset methods
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Reads the next byte of data from the input stream.
- abstract int read()
- java.io.InputStream
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abstract int read()
- java.io.InputStream
- Reads the next byte of data from the input stream.
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Reads some number of bytes from the input stream and stores them into the buffer array b
- int read(byte[ ] b)
- java.io.InputStream
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int read(byte[ ] b)
- java.io.InputStream
- Reads some number of bytes from the input stream and stores them into the buffer array b
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Attempts to reads up to "len" bytes of data from the input stream into buffer array "b" starting at "b[off]"
- int read(byte[ ] b, int off, int len)
- java.io.InputStream
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int read(byte[ ] b, int off, int len)
- java.io.InputStream
- Attempts to reads up to "len" bytes of data from the input stream into buffer array "b" starting at "b[off]"
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Resets the input pointer to the previously "set" mark
- void reset()
- java.io.InputStream
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void reset()
- java.io.InputStream
- Resets the input pointer to the previously "set" mark
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Skips over and discards n bytes of data from this input stream.
- long skip(long n)
- java.io.InputStream
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long skip(long n)
- java.io.InputStream
- Skips over and discards n bytes of data from this input stream.
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Methods of java.io.OutputStream (5)
- 1 - void close()
- 2 - void flush()
- 3 - void write(int b)
- 4 - void write(byte[ ] b)
- 5 - void write(byte[ ] b, int off, int len)
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Closes this output stream
- void close()
- java.io.OutputStream
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void close()
- java.io.OutputStream
- Closes this output stream
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Causes any output that has been buffered to be sent to its destination. That is "flashes" the output buffer
- void flush()
- java.io.OutputStream
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void flush()
- java.io.OutputStream
- Causes any output that has been buffered to be sent to its destination. That is "flashes" the output buffer
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Writes the single specified byte to this output stream
- void write(int b)
- java.io.OutputStream
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void write(int b)
- java.io.OutputStream
- Writes the single specified byte to this output stream
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Writes b.length bytes from the specified byte array to this output stream
- void write(byte[ ] b)
- java.io.OutputStream
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void write(byte[ ] b)
- java.io.OutputStream
- Writes b.length bytes from the specified byte array to this output stream
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Writes "len" bytes from the specified byte array starting at offset "off" to this output stream
- void write(byte[ ] b, int off, int len)
- java.io.OutputStream
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void write(byte[ ] b, int off, int len)
- java.io.OutputStream
- Writes "len" bytes from the specified byte array starting at offset "off" to this output stream
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