@Synchronized
    public boolean updateUserConfig(@NonNull String prop, @NonNull String value) {
        try {
            if (value.equals(userProperties.get(prop))) {
                return false;
            }

            userProperties.setProperty(prop, value);

            USER_CONFIG_FILE.createNewFile();
            try (OutputStream outputStream = new FileOutputStream(USER_CONFIG_FILE)) {
                userProperties.store(outputStream, "Modified by Testcontainers");
            }

            // Update internal state only if environment config was successfully updated
            userProperties.setProperty(prop, value);
            return true;
        } catch (Exception e) {
            log.debug("Can't store environment property {} in {}", prop, USER_CONFIG_FILE);
            return false;
        }
    }
@return properties values available from user properties and classpath properties. Values set by environment
variable are NOT included.
@deprecated usages should be removed ASAP. See {@link TestcontainersConfiguration#getEnvVarOrProperty(String, String)},
{@link TestcontainersConfiguration#getEnvVarOrUserProperty(String, String)} or {@link TestcontainersConfiguration#getUserProperty(String, String)}
for suitable replacements.
core/src/main/java/org/testcontainers/utility/TestcontainersConfiguration.java