abstract class AbstractStringBuilder implements Appendable, CharSequence { /** * The value is used for character storage. */ char value[]; /** * The count is the number of characters used. */ int count; /** * This no-arg constructor is necessary for serialization of subclasses. */ AbstractStringBuilder() { } /** * Creates an AbstractStringBuilder of the specified capacity. */ AbstractStringBuilder(int capacity) { value = new char[capacity]; }
Now take a look at this:
java.lang.NullPointerException at java.lang.System.arraycopy(Native Method) at java.lang.AbstractStringBuilder.getChars(AbstractStringBuilder.java:328) at java.lang.StringBuffer.getChars(StringBuffer.java:201) at org.apache.log4j.helpers.ISO8601DateFormat.format(ISO8601DateFormat.java:130) at java.text.DateFormat.format(DateFormat.java:316) at org.apache.log4j.helpers.PatternParser$DatePatternConverter.convert(PatternParser.java:443) at org.apache.log4j.helpers.PatternConverter.format(PatternConverter.java:65) at org.apache.log4j.PatternLayout.format(PatternLayout.java:506) at org.apache.log4j.WriterAppender.subAppend(WriterAppender.java:310) at org.apache.log4j.RollingFileAppender.subAppend(RollingFileAppender.java:276) at org.apache.log4j.WriterAppender.append(WriterAppender.java:162) at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251) at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66) at org.apache.log4j.Category.callAppenders(Category.java:206) at org.apache.log4j.Category.forcedLog(Category.java:391) at org.apache.log4j.Category.log(Category.java:856) at org.slf4j.impl.Log4jLoggerAdapter.error(Log4jLoggerAdapter.java:571)
Sure,
values
can easily be null, eh.