多选题

下列那些方法是线程安全的(所调用的方法都存在)

Question

A. public class MyServlet implements Servlet { public void service (ServletRequest req, ServletResponse resp) { BigInteger I = extractFromRequest(req) encodeIntoResponse(resp,factors) } }

B. public class MyServlet implements Servlet { private long count =0 public long getCount() { return count } public void service (ServletRequest req, ServletResponse resp) { BigInteger I = extractFromRequest(req) BigInteger[] factors = factor(i) count ++ encodeIntoResponse(resp,factors) } }

C. public class MyClass { private int value public synchronized int get() { return value } public synchronized void set (int value) { this.value = value } }

D. public class Factorizer implements Servlet { private volatile MyCache cache = new MyCache(null,null) public void service(ServletRequest req, ServletResponse resp) { BigInteger i = extractFromRequest(req) BigInteger[] factors = cache.getFactors(i) if (factors == null) { factors = factor(i) cache = new MyCache(i,factors) } encodeIntoResponse(resp,factors) }