SystemPropertyArbiter variable assignment error

// org.apache.logging.log4j.core.config.arbiters.SystemPropertyArbiter
public static final String ATTR_PROPERTY_NAME = "propertyName";
public static final String ATTR_PROPERTY_VALUE = "propertyValue";

@PluginBuilderAttribute(ATTR_PROPERTY_NAME)
private String propertyName;

@PluginBuilderAttribute(ATTR_PROPERTY_VALUE)
private String propertyValue;
/**
 * Sets the Property Name.
 * @param propertyName the property name.
 * @return this
 */
public Builder setPropertyName(final String propertyName) {
    this.propertyName = propertyName;
    return asBuilder();
}

/**
 * Sets the Property Value.
 * @param propertyValue the property name.
 * @return this
 */
public Builder setPropertyValue(final String propertyValue) {
    this.propertyName = propertyValue;
    return asBuilder();
}