.\"
.\" Copyright (C) 2005 Greg Lewis. All rights reserved.
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.\" $FreeBSD$
.\"
.Dd February 24, 2005
.Os
.Dt JAVAVM 1
.Sh NAME
.Nm javavm
.Nd convenient wrapper for switching Java VMs
.Sh SYNOPSIS
.Nm
.Op Ar arguments ...
.Sh DESCRIPTION
The Java VM wrapper provides a convenient system for switching between
different Java VMs.
It also provides symbolic links in
.Pa %%LOCALBASE%%/bin
to allow the use of
the Java executables without having to add the specific Java VM executable
directories to the
.Ev PATH
environment variable.
.Pp
The
.Nm
utility itself is currently a synonym for
.Dq java .
However, this behaviour
is deprecated and is provided only for compatibility with the previous
version of
.Nm .
This functionality may be removed in a future version and should not be
relied upon.
.Pp
By default,
.Nm
will select the most
.Dq native
and up to date version of the Java VM when
a given symbolic link is used, invoking and passing the arguments to the
matching executable within the chosen Java VM.
The choice of Java VM may also be influenced by using environment variables
to constrain the version, vendor and operating system of the Java VM.
.Pp
This selection process is usually achieved through the use of
.Pa %%PORTSDIR%%/Mk/bsd.java.mk .
However, if this is not present then
.Nm
will use its own internal selection process which is
designed to behave almost identically.
.Sh ENVIRONMENT
.Bl -tag -width indent
.It Ev JAVA_HOME
The presence of this variable in the environment when executing
.Nm
will override all other considerations regarding the Java VM to be used
and the Java VM located at
.Pa ${JAVA_HOME}/bin/java
will be used.
.Pp
This variable is set by
.Nm
when executing the actual Java VM and will be available to it and all of
its child processes.
.It Ev JAVA_OS
A space delimited list of operating systems.
The selected Java VM must have been created for one of the operating systems
in the list.
.Pp
Currently allowed operating system values are
.Ql native
and
.Ql linux .
.It Ev JAVA_VENDOR
A space delimited list of Java VM vendors.
The selected Java VM must have been released by one of the vendors in the list.
.Pp
Currently allowed vendors are
.Ql bsdjava ,
.Ql freebsd ,
.Ql blackdown ,
.Ql ibm
and
.Ql sun .
.It Ev JAVA_VERSION
A space delimited list of versions of the Java VM that may be used.
By appending a
.Ql +
to a version, any Java VM with a version greater than or
equal to the given version will be used.
.Pp
Currently allowed versions are
.Ql 1.1 ,
.Ql 1.1+ ,
.Ql 1.2 ,
.Ql 1.2+ ,
.Ql 1.3 ,
.Ql 1.3+ ,
.Ql 1.4 ,
.Ql 1.4+ ,
.Ql 1.5
and
.Ql 1.5+ .
.El
.Sh FILES
.Bl -tag -width indent
.It Pa %%PREFIX%%/etc/javavms
The location of the Java VM wrapper configuration file.
.It Pa %%PORTSDIR%%/Mk/bsd.java.mk
The file usually used, along with
.Nm make ,
to select the Java VM to be used.
.El
.Sh EXAMPLES
.Bl -tag -width indent
.It Pa %%LOCALBASE%%/bin/java
Execute the most up to date and
.Dq native
Java VM registered with
.Nm .
.It Ev JAVA_VERSION=1.4+ Pa %%LOCALBASE%%/bin/javac MyClass.java
Compile MyClass.java with a registered Java VM's javac that is at least
version 1.4.
.It Ev JAVA_OS=native Pa %%LOCALBASE%%/bin/java Fl jar Pa MyApp.jar
Execute MyApp with the most up to date native Java VM that is registered
with
.Nm .
This is necessary if MyApp uses JNI, for instance.
.It Ev JAVA_VERSION="1.2 1.4" Pa %%LOCALBASE%%/bin/java Fl jar Pa MyApp.jar
Execute MyApp with either a Java VM that is either version 1.2 or version 1.4.
.El
.Sh SEE ALSO
.Xr checkvms 1 ,
.Xr make 1 ,
.Xr registervm 1 ,
.Xr unregistervm 1 ,
.Xr javavms 5
.Sh BUGS
The internal selection procedure of
.Nm
is not fully identical to that used when
.Pa %%PORTSDIR%%/Mk/bsd.java.mk
is present.
In particular,
.Nm
does not respect environment variables such as
.Ev JAVA_PREFERRED_PORTS
which is used by
.Pa %%PORTSDIR%%/Mk/bsd.java.mk
and will not use the values of such variables if they are set up as
.Nm make
variables in
.Pa /etc/make.conf ,
for example.