Effective Java 2nd Edition - Revision history

Fukakai: /* Key points */

2025-10-05T21:31:41Z

Key points

← Older revision		Revision as of 23:31, 5 October 2025
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	* '''Item 66 – Synchronize access to shared mutable data''' Use synchronization or concurrency utilities to prevent race conditions.		* '''Item 66 – Synchronize access to shared mutable data''' Use synchronization or concurrency utilities to prevent race conditions.
	* '''Item 68 – Prefer executors and tasks to threads''' Use:		* '''Item 68 – Prefer executors and tasks to threads''' Use:
	<~~nowiki><~~code>ExecutorService executor = Executors.newFixedThreadPool(10);</~~code></nowiki~~>		<pre class="code java">ExecutorService executor = Executors.newFixedThreadPool(10);</pre>
	* '''Item 69 – Prefer concurrency utilities to wait and notify''' Use <code>BlockingQueue</code>, <code>CountDownLatch</code>, etc., instead of manual thread coordination.		* '''Item 69 – Prefer concurrency utilities to wait and notify''' Use <code>BlockingQueue</code>, <code>CountDownLatch</code>, etc., instead of manual thread coordination.

Fukakai: /* Key points */

2025-10-05T21:31:25Z

Key points

← Older revision		Revision as of 23:31, 5 October 2025
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	* '''Item 38 – Check parameters for validity''' Validate arguments early, e.g.:		* '''Item 38 – Check parameters for validity''' Validate arguments early, e.g.:
	<~~nowiki~~>~~<code~~>this.range = Objects.requireNonNull(range);</~~code></nowiki~~>		<pre class="code java">>this.range = Objects.requireNonNull(range);</pre>
	* '''Item 39 – Make defensive copies when needed''' Prevent callers from modifying internal state:		* '''Item 39 – Make defensive copies when needed''' Prevent callers from modifying internal state:
	<~~nowiki><~~code>this.start = new Date(start.getTime());</~~code></nowiki~~>		<pre class="code java">this.start = new Date(start.getTime());</pre>
	* '''Item 40 – Design method signatures carefully''' Keep APIs small, intuitive, and consistent.		* '''Item 40 – Design method signatures carefully''' Keep APIs small, intuitive, and consistent.

Fukakai: /* Key points */

2025-10-05T21:31:07Z

Key points

← Older revision		Revision as of 23:31, 5 October 2025
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	* '''Item 25 – Prefer lists to arrays''' Arrays are covariant and unsafe, while generics are type-safe.		* '''Item 25 – Prefer lists to arrays''' Arrays are covariant and unsafe, while generics are type-safe.
	* '''Item 26 – Favor generic methods'''		* '''Item 26 – Favor generic methods'''
	<~~nowiki><~~code>public static <E> Set<E> union(Set<E> s1, Set<E> s2) { ... }</~~code></nowiki~~>		<pre class="code java">public static <E> Set<E> union(Set<E> s1, Set<E> s2) { ... }</pre>
	* '''Item 27 – Use bounded wildcards to increase API flexibility'''		* '''Item 27 – Use bounded wildcards to increase API flexibility'''
	** <code><? extends T></code> for producers		** <code><? extends T></code> for producers

Fukakai: /* Key points */

2025-10-05T21:30:52Z

Key points

← Older revision		Revision as of 23:30, 5 October 2025
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	** Don’t leak <code>this</code> in constructors		** Don’t leak <code>this</code> in constructors
	* '''Item 16 – Favor composition over inheritance''' Inheritance creates tight coupling. Prefer wrapping a member instead:		* '''Item 16 – Favor composition over inheritance''' Inheritance creates tight coupling. Prefer wrapping a member instead:
	<~~nowiki><~~code>class InstrumentedSet<E> extends ForwardingSet<E> { ... }</~~code></nowiki~~>		<pre class="code java">class InstrumentedSet<E> extends ForwardingSet<E> { ... }</pre>
	* '''Item 17 – Design and document for inheritance, or prohibit it''' If you don’t want subclasses, mark the class <code>final</code>.		* '''Item 17 – Design and document for inheritance, or prohibit it''' If you don’t want subclasses, mark the class <code>final</code>.
	* '''Item 18 – Prefer interfaces to abstract classes''' A class can implement multiple interfaces but extend only one class.		* '''Item 18 – Prefer interfaces to abstract classes''' A class can implement multiple interfaces but extend only one class.

Fukakai: /* Key points */

2025-10-05T21:30:19Z

Key points

← Older revision		Revision as of 23:30, 5 October 2025
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	* '''Item 2 – Consider a builder when faced with many constructor parameters''' Use the '''Builder pattern''' to replace telescoping constructors:		* '''Item 2 – Consider a builder when faced with many constructor parameters''' Use the '''Builder pattern''' to replace telescoping constructors:

	<code>NutritionFacts cocaCola = new NutritionFacts.Builder(240, 8).calories(100).sodium(35).carbohydrate(27).build();</~~code~~>		<pre class="code java">
			NutritionFacts cocaCola = new NutritionFacts.Builder(240, 8)
			.calories(100).sodium(35).carbohydrate(27).build();
			</pre>

	* '''Item 3 – Enforce the Singleton property with a private constructor or an enum''' Prefer <code>enum</code> singletons:		* '''Item 3 – Enforce the Singleton property with a private constructor or an enum''' Prefer <code>enum</code> singletons:

Fukakai: /* Key points */

2025-10-05T21:29:41Z

Key points

← Older revision		Revision as of 23:29, 5 October 2025
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	* '''Item 1 – Consider static factory methods instead of constructors''' Static factories have names, can return cached instances or subtypes, and allow better control of object creation.		* '''Item 1 – Consider static factory methods instead of constructors''' Static factories have names, can return cached instances or subtypes, and allow better control of object creation.

	<code>Boolean.valueOf(true);</~~code~~>		<pre class="code java">Boolean.valueOf(true);</pre>

	* '''Item 2 – Consider a builder when faced with many constructor parameters''' Use the '''Builder pattern''' to replace telescoping constructors:		* '''Item 2 – Consider a builder when faced with many constructor parameters''' Use the '''Builder pattern''' to replace telescoping constructors:
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	* '''Item 3 – Enforce the Singleton property with a private constructor or an enum''' Prefer <code>enum</code> singletons:		* '''Item 3 – Enforce the Singleton property with a private constructor or an enum''' Prefer <code>enum</code> singletons:
	<code>public enum Elvis { INSTANCE; }</~~code~~>		<pre class="code java">public enum Elvis { INSTANCE; }</pre>
	* '''Item 5 – Prefer dependency injection to hardwiring resources''' Pass dependencies through constructors instead of creating them internally.		* '''Item 5 – Prefer dependency injection to hardwiring resources''' Pass dependencies through constructors instead of creating them internally.
	* '''Item 7 – Avoid finalizers''' They’re unreliable and slow. Use <code>try-with-resources</code> or <code>Cleaner</code> instead.		* '''Item 7 – Avoid finalizers''' They’re unreliable and slow. Use <code>try-with-resources</code> or <code>Cleaner</code> instead.

Fukakai: /* Key points */

2025-10-05T21:29:22Z

Key points

← Older revision		Revision as of 23:29, 5 October 2025
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	* '''Item 10 – Always override <code>toString</code>''' Make it human-readable and useful for debugging/logging.		* '''Item 10 – Always override <code>toString</code>''' Make it human-readable and useful for debugging/logging.
	* '''Item 12 – Consider implementing <code>Comparable</code>''' Enables sorting and ordering:		* '''Item 12 – Consider implementing <code>Comparable</code>''' Enables sorting and ordering:
	<code java>
	public int compareTo(PhoneNumber pn) {		<pre class="code java">
	int result = Short.compare(areaCode, pn.areaCode);		public int compareTo(PhoneNumber pn) {
	if (result == 0)		int result = Short.compare(areaCode, pn.areaCode);
	result = Short.compare(prefix, pn.prefix);		if (result == 0)
	if (result == 0)		result = Short.compare(prefix, pn.prefix);
	result = Short.compare(lineNum, pn.lineNum);		if (result == 0)
	return result;		result = Short.compare(lineNum, pn.lineNum);
	}		return result;
	</~~code~~>		}
			</pre>
	----		----

Fukakai: /* Key points */

2025-10-05T21:23:33Z

Key points

← Older revision		Revision as of 23:23, 5 October 2025
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	* '''Item 10 – Always override <code>toString</code>''' Make it human-readable and useful for debugging/logging.		* '''Item 10 – Always override <code>toString</code>''' Make it human-readable and useful for debugging/logging.
	* '''Item 12 – Consider implementing <code>Comparable</code>''' Enables sorting and ordering:		* '''Item 12 – Consider implementing <code>Comparable</code>''' Enables sorting and ordering:
	<code>		<code java>

	public int compareTo(PhoneNumber pn) {		public int compareTo(PhoneNumber pn) {

	int result = Short.compare(areaCode, pn.areaCode);		int result = Short.compare(areaCode, pn.areaCode);

	if (result == 0)		if (result == 0)

	result = Short.compare(prefix, pn.prefix);		result = Short.compare(prefix, pn.prefix);

	if (result == 0)		if (result == 0)

	result = Short.compare(lineNum, pn.lineNum);		result = Short.compare(lineNum, pn.lineNum);

	return result;		return result;

	}		}

	</code>		</code>
	----		----

Fukakai: /* 2. Methods Common to All Objects */

2025-10-05T21:23:01Z

2. Methods Common to All Objects

← Older revision		Revision as of 23:23, 5 October 2025
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	* '''Item 10 – Always override <code>toString</code>''' Make it human-readable and useful for debugging/logging.		* '''Item 10 – Always override <code>toString</code>''' Make it human-readable and useful for debugging/logging.
	* '''Item 12 – Consider implementing <code>Comparable</code>''' Enables sorting and ordering:		* '''Item 12 – Consider implementing <code>Comparable</code>''' Enables sorting and ordering:
	~~<nowiki>~~<code~~></nowiki~~>		<code>

	public int compareTo(PhoneNumber pn) {		public int compareTo(PhoneNumber pn) {
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	}		}

	~~<nowiki>~~</code~~></nowiki~~>		</code>
	----		----

Fukakai: /* Key points */

2025-10-05T21:22:41Z

Key points

← Older revision		Revision as of 23:22, 5 October 2025
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	* '''Item 1 – Consider static factory methods instead of constructors''' Static factories have names, can return cached instances or subtypes, and allow better control of object creation.		* '''Item 1 – Consider static factory methods instead of constructors''' Static factories have names, can return cached instances or subtypes, and allow better control of object creation.

	~~<nowiki>~~<code>Boolean.valueOf(true);</code~~></nowiki~~>		<code>Boolean.valueOf(true);</code>

	* '''Item 2 – Consider a builder when faced with many constructor parameters''' Use the '''Builder pattern''' to replace telescoping constructors:		* '''Item 2 – Consider a builder when faced with many constructor parameters''' Use the '''Builder pattern''' to replace telescoping constructors:

	~~<nowiki>~~<code>~~</nowiki>~~		<code>NutritionFacts cocaCola = new NutritionFacts.Builder(240, 8).calories(100).sodium(35).carbohydrate(27).build();</code>

	NutritionFacts cocaCola = new NutritionFacts.Builder(240, 8).calories(100).sodium(35).carbohydrate(27).build();

	~~<nowiki>~~</code~~></nowiki~~>

	* '''Item 3 – Enforce the Singleton property with a private constructor or an enum''' Prefer <code>enum</code> singletons:		* '''Item 3 – Enforce the Singleton property with a private constructor or an enum''' Prefer <code>enum</code> singletons:
	~~<nowiki>~~<code>public enum Elvis { INSTANCE; }</code~~></nowiki~~>		<code>public enum Elvis { INSTANCE; }</code>
	* '''Item 5 – Prefer dependency injection to hardwiring resources''' Pass dependencies through constructors instead of creating them internally.		* '''Item 5 – Prefer dependency injection to hardwiring resources''' Pass dependencies through constructors instead of creating them internally.
	* '''Item 7 – Avoid finalizers''' They’re unreliable and slow. Use <code>try-with-resources</code> or <code>Cleaner</code> instead.		* '''Item 7 – Avoid finalizers''' They’re unreliable and slow. Use <code>try-with-resources</code> or <code>Cleaner</code> instead.