logback-android/src/main/java/ch/qos/logback/core/net/SMTPAppenderBase.java
public boolean checkEntryConditions() {
    if (!this.started) {
      addError("Attempting to append to a non-started appender: "
              + this.getName());
      return false;
    }

    if (this.eventEvaluator == null) {
      addError("No EventEvaluator is set for appender [" + name + "].");
      return false;
    }

    if (this.layout == null) {
      addError("No layout set for appender named ["
              + name
              + "]. For more information, please visit http://logback.qos.ch/codes.html#smtp_no_layout");
      return false;
    }
    return true;
  }
public boolean checkEntryConditions() {
    if (!this.started) {
      addError("Attempting to append to a non-started appender: "
              + this.getName());
      return false;
    }

    if (this.eventEvaluator == null) {
      addError("No EventEvaluator is set for appender [" + name + "].");
      return false;
    }

    if (this.layout == null) {
      addError("No layout set for appender named ["
              + name
              + "]. For more information, please visit http://logback.qos.ch/codes.html#smtp_no_layout");
      return false;
    }
    return true;
  }
This method determines if there is a sense in attempting to append.
<p>
It checks whether there is a set output target and also if there is a set
layout. If these checks fail, then the boolean value <code>false</code> is
returned.
@return true if appender is setup properly