Blocking

The following blocking operations are virtual thread friendly; these methods "release" the underlying carrier thread when the operation blocks.

API	Method(s)	Notes
java.lang.Thread	sleep, join	join to wait for a virtual thread to terminate
java.util.concurrent	All blocking operations
java.net.Socket	connect, read, write	Socket constructors with a host name parameter may need to do a lookup with InetAddress, see below
java.net.ServerSocket	accept
java.net.DatagramSocket/MulticastSocket	receive	connect, disconnect and send do not block
java.nio.channels.SocketChannel	connect, read, write	socket adaptor connect, read, and write also okay
java.nio.channels.ServerSocketChannel	accept	socket adaptor accept also okay
java.nio.channels.DatagramChannel	read, receive	socket adaptor receive also okay connect, disconnect, send, and write do not block
java.nio.channels.Pipe.SourceChannel	read
java.nio.channels.Pipe.SinkChannel	write
Console streams (System.in, out, err)	read, write, printf	Linux/macOS only at this time.

The following blocking operations use the ForkJoinPool.ManagedBocker mechanism when invoked from a virtual thread. Parallelism is temporarily extended until the blocking operation completes.

API	Method(s)
java.lang.Object	wait
java.io.File	All file I/O operations
java.io.FileInputStream	open, read, skip
java.io.FileOutputStream	open, write
java.io.RandomAccessFile	open, read, write, seek
java.net.InetAddress	All lookup operations
java.nio.MappedByteBuffer	force
java.nio.channels.Selector	All blocking selection operations
java.nio.channels.FileChannel	read, write, lock, truncate, force, transferTo
java.nio.file	All file I/O operations

The following blocking operations use the ForkJoinPool.ManagedBocker mechanism by way of operations in the previous table.

API	Method(s)	Notes
java.lang.Thread	join	join to wait for a kernel thread to terminate
java.io.Console	read, write, printf	Windows only
java.lang.Process	input/output/error streams