ordersToUpdate.stream().forEach((o) -> {
                try {
                    o.waitForUpdate(ORDER_TIMEOUT, CLOSED, CANCELED);
                } catch (JFException e) {
                    warn("Caught a JFException when close order #", o.getId(), " - "
                            , e.toString());
                }
            });

When I compile the codes above,these errors come out:
2017-10-30 14:29:14 1. ERROR in ...\jfxide\tmp\compile\Test.java (at line 154)
2017-10-30 14:29:14 ordersToUpdate.stream().forEach((o) -> {
2017-10-30 14:29:14 ________________try_{
2017-10-30 14:29:14 ^^^^^^^^^^^^^^^^^^^^^^^^^^
2017-10-30 14:29:14 Syntax error on tokens, delete these tokens

May someone help me?

By the way,those codes below can be compiled as well:

for (IOrder o : ordersToUpdate) {
                try {
                    o.waitForUpdate(ORDER_TIMEOUT, CLOSED, CANCELED);
                } catch (JFException e) {
                    warn("Caught a JFException when close order #", o.getId(), " - "
                            , e.toString());
                }
            }

So, I doubt that, .stream().forEach can't be compiled in JForex. Is that right?

Yes, currently we support only Java 7 in the JForex Client editor.