public class FSTClazzInfoRegistry {     ... ...  public FSTClazzInfo getCLInfo(Class c) {        //1).此处会出现死循环，而且线程一直是运行状态        while(!rwLock.compareAndSet(false,true));        FSTClazzInfo res = (FSTClazzInfo) mInfos.get(c);        if ( res == null ) {            if ( c == null ) {                rwLock.set(false);                throw new NullPointerException("Class is null");            }            //2).在构造FSTClazzInfo对象时会抛出运行时异常，一旦抛出异常造成代码1处死循环            res = new FSTClazzInfo(c, this, ignoreAnnotations);            mInfos.put( c, res );        }        rwLock.set(false);        return res;    } ... ...}public final class FSTClazzInfo {	... ...    public FSTClazzInfo(Class clazz, FSTClazzInfoRegistry infoRegistry, boolean ignoreAnnotations) {        this.clazz = clazz;        enumConstants = clazz.getEnumConstants();        reg = infoRegistry;        ignoreAnn = ignoreAnnotations;        createFields(clazz);        if ( !reg.isStructMode() ) {            if (Externalizable.class.isAssignableFrom(clazz)) {                externalizable = true;                cons = FSTUtil.findConstructorForExternalize(clazz);            } else if (Serializable.class.isAssignableFrom(clazz) || clazz == Object.class ) {                externalizable = false;                cons = FSTUtil.findConstructorForSerializable(clazz);            } else {                //3).一旦需要序列化的对象没有实现Serializable接口或Externalizable接口的话，就会抛出运行时异常                throw new RuntimeException("Class "+clazz.getName()+" does not implement Serializable or externalizable");            }            if ( ! ignoreAnnotations ) {                Predict annotation = (Predict) clazz.getAnnotation(Predict.class);                if (annotation != null) {                    predict = annotation.value();                } else {                       //default predictions (disabled, no speedup)//                    if ( clazz == List.class ) {//                        predict = new Class[]{ArrayList.class};//                    } else if ( clazz == Map.class ) {//                        predict = new Class[]{HashMap.class};//                    }                }                equalIsIdentity = clazz.isAnnotationPresent(EqualnessIsIdentity.class);                equalIsBinary = clazz.isAnnotationPresent(EqualnessIsBinary.class);                flat = clazz.isAnnotationPresent(Flat.class);            }        }        if (cons != null) {            cons.setAccessible(true);        }        final String name = clazz.getName();        if (name.length()<127) {            isAsciiNameShortString = true;            for (int i=0; i < name.length();i++) {                if (name.charAt(i) > 127) {                    isAsciiNameShortString = false;                    break;                }            }        }        requiresInit = isExternalizable() || useCompatibleMode() || hasTransient;    }   ... ...}