use IPC::Open2 qw( open2 );
use IPC::Open3 qw( open3 );

# this works:
my $kid = 
  open(FH1, "java -classpath $PATH TextEntry");
my $kid = 
  open2(FH1, FH2, "java -classpath $PATH TextEntry");
my $kid = 
  open3(FH1, FH2, FH3, "java -classpath $PATH TextEntry");

# however, when I try to suppress stderr,
# it doesn't work because of the redirection,
# and the process is launched it in a shell;
# $kid is the pid of the shell:
my $kid = 
  open(FH1, "java -classpath $PATH TextEntry 2> /dev/null");
my $kid =
  open2(FH1, FH2, "java -classpath $PATH TextEntry 2> /dev/null");

# no problem, open3() will capture STDERR, taking
# care of the redirection:
my $kid =
  open3(FH1, FH2, FH3, "java -classpath $PATH TextEntry");

# however, the use IPC::Open2() docs
# (to which IPC::Open3() is compared to)
# indicates that the above form would be run in a shell,
# so it may be safer to do this:
my $kid =
  open3(FH1, FH2, FH3, "java", "-classpath", "$PATH", "TextEntry");

# but there is a way to capture the child output
# using open() and still kill it when parent exits:
# exec the command from the shell, thus
# $kid = pid of shell = pid of the command
# suggested by ikegami:
my $kid = 
  open(FH1, "exec java -classpath $PATH TextEntry 2> /dev/null");