Exam App Questions
Description
The Exam Application is part of an ongoing effort at Terracotta to define and document a User Session test case from conception to deployment.
This page is a place to add content for the Exam application itself.
Exam Subject - Terracotta
Format - Test Format TBD
Example questions:
What is a Root
What is an Auto Lock
What is a TIM
Can I fit more objects in a shared object graph than what can fit in a JVM
Does wait and notify work in a cluster
How does one find out when nodes join and leave the cluster
What are three ways of configuring your roots, locks and includes
How can one see what objects are in a cluster and each Client jvm
Questions - A list of possible Exam App questions
When you set a TC properties through tc-config.xml, local tc.properties and JVM args, which order of precedence is correct? (Hung)
a) tc-config.xml, local tc.properties, JVM args
b) local tc.properties, tc-config.xml, JVM args
c) JVM args, local tc.properties, tc-config.xml
d) local tc.properties, JVM args, tc-config.xml
Answer: c
What is Terracotta
a) JVM
b) OS Library
c) Caching tool
d) JVM Level Clustering solution
Answer: d
How can you cut off an object graph to prevent state from being unnecessarily clustered? (Geert)
a) Write custom serialization logic by implementing writeObject and readObject.
b) Configure the appropriate fields to be transient for the cluster.
c) Exclude the classes that you don't want to share in the Terracotta configuration.
d) Detect that Terracotta is running and assign 'null' to certain fields.
Answer: b
Under what circumstances will a thread requesting a concurrent lock be blocked? (Walter)
a) requesting a concurrent lock never blocks the requestor; concurrent "locks" aren't really locks at all and should in general be avoided.
b) the requestor will be blocked if another thread in the same VM already owns the lock
c) the requestor will be blocked if another thread anywhere in the cluster already owns the lock
d) the requestor will be blocked until all threads in the cluster line up at the lock, and then one thread will be arbitrarily chosen to unblock.
Answer: a
Using Terracotta requires you to maintain crazy amounts of XML configuration
a) True
b) False
Answer: b (Annotations)
Terracotta is a Distributed Cache
a) True
b) False
Answer: b
Terracotta installations can be configured with no Single Points of Failure
a) True
b) False
Answer: a
How many lock-levels does Terracotta support?
a) 1 (synchronized)
b) 2 (read and write)
c) 3 (read, write and reentrant)
d) 4 (read, write, synchronous-write, and concurrent)
e) 4 (read, write, reentrant, and concurrent)
f) 5 (read, write, reentrant, concurrent, and greedy)
Answer: d
True or False. "dirty reads" of certain data types (e.g. Integers) are safe because they are changed atomically.
a) True
b) False
Answer: b
a bunch of code puzzles created by developers where people need
to try to figure out what would happen etc
Which "outdoor" game is frequently on display "indoors" at Terracotta?
a) Football (american version)
b) Football (soccer to the americans)
c) Frisbee Golf
d) Tennis
Answer: b
What would be printed out below if you run with Terracotta. "map" is declared as a root. (Hung)
public class Main {
private Map map = new ConcurrentHashMap();
public void run() {
Map newMap = new ConcurrentHashMap();
newMap.put("key1", "value1");
newMap.put("key1", "value2");
map = newMap;
System.out.println("Map size: " + map.size());
}
public static void main(String[] args) {
new Main().run();
}
}
a) Map size: 0
b) Map size: 1
c) Map size: 2
Answer: a
True/false - Terracotta instances which are to be clustered must implement Serializable
Answer: false
True/false - Terracotta honors the semantics of the Java Memory Model (locking, synchronization, wait/notify, etc.) across the entire cluster.
a) True, under all circumstances.
b) True, only for operations involving Terracotta clustered instances.
c) True, for all Java classes instrumented by Terracotta.
d) False, the Java Memory model is only guaranteed at each local node.
Answer: c
