No need for open3. 

sub backticks {
  open(my $pipe, '-|', @_)
     or return;
  local $/ = wantarray ? $/ : undef;
  <$pipe>
}

my $java_output = backticks('java', '--classpath=...', ...);

[download]

Bonus: Handles context and errors just like the real thing.

In reply to Re^2: CLASSPATH problem when using backticks by ikegami
in thread CLASSPATH problem when using backticks by maithree

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