if (r.exitCode != 0) {
            throw new AssertionError(String.join(" ", cmd) + " failed: " + r);
        }
    }

    private static String stdout(String... cmd) throws IOException, InterruptedException {
        ExecResult r = exec(cmd);
        if (r.exitCode != 0) {
            throw new AssertionError(String.join(" ", cmd) + " failed: " + r);
        }
        return r.stdout;
    }

            return accessor.getBinaryCompatibility() == BinaryCompatibility.ACCESSORS_KEPT;
        });
        if (!keptAccessors.isEmpty()) {
            String formattedLeft = CollectionUtils.join("\n", keptAccessors.keySet());
            throw new RuntimeException("The following accessors were upgraded, but didn't match any removed/changed method:\n\n" + formattedLeft);
        }

        // Start all threads
        for (Thread thread : threads) {
            thread.start();
        }

        // Wait for all threads to complete
        for (Thread thread : threads) {
            thread.join();
        }

        // Verify no exceptions occurred
        for (int i = 0; i < threadCount; i++) {
            assertNull(exceptions[i], "Thread " + i + " threw exception");

     *
     * @return compact string representation of the mapping rule
     */
    public String toLineString() {
        if (isUpdated()) {
            return StringUtils.join(newInputs, ",") + "=>" + newOutput;
        }
        return StringUtils.join(inputs, ",") + "=>" + output;
    }

     *
     * @return The stopword as a string.
     */
    public String toLineString() {
        if (isUpdated()) {
            return StringUtils.join(newInput);
        }
        return StringUtils.join(input);
    }

     * @return the string representation of this item
     */
    public String toLineString() {
        if (isUpdated()) {
            return StringUtils.join(newInput);
        }
        return StringUtils.join(input);
    }

            }
        });

        // Start both threads
        threads[0].start();
        threads[1].start();

        // Wait for completion
        threads[0].join();
        threads[1].join();

        // Verify no exceptions occurred (the main goal is no ConcurrentModificationException)
        assertNull(exceptions[0], "Add thread threw exception");

            cmdList.add(StringUtils.join(webConfigIds, ','));
        }
        if (fileConfigIds != null && fileConfigIds.length > 0) {
            cmdList.add("-f");
            cmdList.add(StringUtils.join(fileConfigIds, ','));
        }
        if (dataConfigIds != null && dataConfigIds.length > 0) {
            cmdList.add("-d");
            cmdList.add(StringUtils.join(dataConfigIds, ','));
        }

        if (r.exitCode() != 0) {
            throw new AssertionError(String.join(" ", cmd) + " failed: " + r);
        }
    }

    private static String stdout(String... cmd) throws IOException, InterruptedException, ExecutionException {
        ExecResult r = exec(cmd);
        if (r.exitCode() != 0) {
            throw new AssertionError(String.join(" ", cmd) + " failed: " + r);
        }
        return r.stdout();
    }

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