When I load a 90MB file into a String and try to log it I get the following:
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at java.util.Arrays.copyOf(Unknown Source)
at java.lang.AbstractStringBuilder.expandCapacity(Unknown Source)
at java.lang.AbstractStringBuilder.append(Unknown Source)
at java.lang.StringBuilder.append(Unknown Source)
at ch.qos.logback.core.pattern.FormattingConverter.write(FormattingConverter.java:40)
at ch.qos.logback.core.pattern.PatternLayoutBase.writeLoopOnConverters(PatternLayoutBase.java:119)
at ch.qos.logback.classic.PatternLayout.doLayout(PatternLayout.java:168)
at ch.qos.logback.classic.PatternLayout.doLayout(PatternLayout.java:59)
at ch.qos.logback.core.encoder.LayoutWrappingEncoder.doEncode(LayoutWrappingEncoder.java:134)
at ch.qos.logback.core.OutputStreamAppender.writeOut(OutputStreamAppender.java:188)
at ch.qos.logback.core.FileAppender.writeOut(FileAppender.java:206)
at ch.qos.logback.core.OutputStreamAppender.subAppend(OutputStreamAppender.java:212)
at ch.qos.logback.core.rolling.RollingFileAppender.subAppend(RollingFileAppender.java:175)
at ch.qos.logback.core.OutputStreamAppender.append(OutputStreamAppender.java:103)
at ch.qos.logback.core.UnsynchronizedAppenderBase.doAppend(UnsynchronizedAppenderBase.java:88)
at ch.qos.logback.core.spi.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:48)
at ch.qos.logback.classic.Logger.appendLoopOnAppenders(Logger.java:272)
at ch.qos.logback.classic.Logger.callAppenders(Logger.java:259)
at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:441)
at ch.qos.logback.classic.Logger.filterAndLog_1(Logger.java:413)
at ch.qos.logback.classic.Logger.debug(Logger.java:506)
...

Appender: ch.qos.logback.core.rolling.RollingFileAppender
Pattern: %p %d

%c:%L %X

%m%n

Maybe when the message is too big, it can use a more memory efficient method to log (or reduce functionality).