liquibase-core/src/main/java/liquibase/configuration/ConfigurationProperty.java
public ConfigurationProperty setDefaultValue(Object defaultValue) {
        if ((defaultValue != null) && !type.isAssignableFrom(defaultValue.getClass())) {
            if ((type == Long.class) && (defaultValue instanceof Integer)) {
                return setDefaultValue(((Integer) defaultValue).longValue());
            }
            throw new UnexpectedLiquibaseException("Property "+name+" on is of type "+type.getSimpleName()+", not "+defaultValue.getClass().getSimpleName());
        }

        this.defaultValue = defaultValue;

        return this;
    }
public ConfigurationProperty setDefaultValue(Object defaultValue) {
        if ((defaultValue != null) && !type.isAssignableFrom(defaultValue.getClass())) {
            if ((type == Long.class) && (defaultValue instanceof Integer)) {
                return setDefaultValue(((Integer) defaultValue).longValue());
            }
            throw new UnexpectedLiquibaseException("Property "+name+" on is of type "+type.getSimpleName()+", not "+defaultValue.getClass().getSimpleName());
        }

        this.defaultValue = defaultValue;

        return this;
    }
Sets the default value to use if no ConfigurationProviders override it. Throws an exception if the given object is not compatible with the defined type.