How To Implement The Singleton Pattern From 'Design Patterns' In Java?

2025-06-18 03:40:22 206

1 Answers

Kiera
Kiera
2025-06-20 12:36:58
Implementing the Singleton pattern in Java is one of those classic coding moves that feels like threading a needle—it’s simple in theory but easy to mess up if you don’t pay attention to the details. I’ve seen so many developers trip over lazy initialization or thread safety, so let’s break it down without the fluff. The core idea is to ensure only one instance of a class exists, and you control how it’s accessed. The most bulletproof way is the 'double-checked locking' approach, which nails both efficiency and safety. You start by making the constructor private so no one can just 'new' it up willy-nilly. Then, you declare a private static volatile instance variable—volatile is key here because it stops threads from caching stale data. Inside the getInstance method, you first check if the instance is null (no need to lock if it’s already there), then slap on a synchronized block for the actual creation. This way, you avoid the performance hit of synchronizing every single call while still keeping things thread-safe. It’s like locking the door only when you’re moving valuables, not every time you step out.

Now, if you’re feeling minimalist, the 'enum' method is downright elegant. Java enums are singleton by default—the JVM guarantees it. Just define your enum with a single instance and tack on your methods. No synchronization, no lazy initialization headaches, just a clean, readable solution. But some folks grumble about enums being inflexible or wasting memory, though I’ve rarely seen it matter in practice. For most projects, especially those heavy on dependency injection or frameworks like Spring, you might not even need to hand-roll a Singleton. The framework often handles scope for you. But knowing how to do it manually? That’s like keeping a spare key—unassuming but a lifesaver when things go sideways. And hey, if you’re into testing, remember Singletons can be a pain to mock, so weigh that before going all in.
View All Answers
Scan code to download App

Related Books

Design of Fate
Design of Fate
Book Two of the Dark Moon Series. Beta Jackson Anderson lives for his pack and family. They mean everything to him, but there is still a part of him that longs for his mate and feels unfulfilled each year that passes without finding her. He is definitely surprised when he finds her for two reasons. One, she is not a shifter. Two, she is running for her life. Imeela Precoza has been on the run for the past ten years because she escaped the massacre of her coven, the royal coven of the vampire world. Countless bounty hunters come after her, forcing her to either evade them or kill them before they kill her. She becomes a master of hiding, especially with the use of her abilities, but she wonders if this is how her life will always be – running, escaping, and surviving while being utterly alone in this world. Fate presents the perfect opportunity that will cause these mates' paths to converge. A man who wants nothing more than to protect and care for his mate, and a woman who is terrified of anyone else getting hurt because of her. It is the design of fate that takes everyone by surprise. Secrets from the past will come to light, showing the truth about why Imeela's coven was slaughtered in the first place. What does this have to do with the prophecy foretold in Book One regarding Brynn's destiny to slay a vile evil? Imeela is tired or running and decides it is time to fight back against a tyrant who has destroyed too much in her life. She is not alone any longer and has the help of a multitude of powerful individuals. Can Imeela and Jackson overcome the adversities in their path?
10
100 Chapters
How to Escape from a Ruthless Mobster
How to Escape from a Ruthless Mobster
Beatrice Carbone always knew that life in a mafia family was full of secrets and dangers, but she never imagined she would be forced to pay the highest price: her own future. Upon returning home to Palermo, she discovers that her father, desperate to save his business, has promised her hand to Ryuu Morunaga, the enigmatic and feared heir of one of the cruelest Japanese mafia families. With a cold reputation and a ruthless track record, Ryuu is far from the typical "ideal husband." Beatrice refuses to see herself as the submissive woman destiny has planned for her. Determined to resist, she quickly realizes that in this game of power and betrayal, her only choice might be to become as dangerous as those around her. But amid forced alliances, dark secrets, and an undeniable attraction, Beatrice and Ryuu are swept into a whirlwind of tension and desire. Can she survive this marriage without losing herself? Or will the dangerous world of the Morunagas become both her home and her prison?
Not enough ratings
98 Chapters
HOW TO LOVE
HOW TO LOVE
Is it LOVE? Really? ~~~~~~~~~~~~~~~~~~~~~~~~ Two brothers separated by fate, and now fate brought them back together. What will happen to them? How do they unlock the questions behind their separation? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
10
2 Chapters
How to Settle?
How to Settle?
"There Are THREE SIDES To Every Story. YOURS, HIS And The TRUTH."We both hold distaste for the other. We're both clouded by their own selfish nature. We're both playing the blame game. It won't end until someone admits defeat. Until someone decides to call it quits. But how would that ever happen? We're are just as stubborn as one another.Only one thing would change our resolution to one another. An Engagement. .......An excerpt -" To be honest I have no interest in you. ", he said coldly almost matching the demeanor I had for him, he still had a long way to go through before he could be on par with my hatred for him. He slid over to me a hot cup of coffee, it shook a little causing drops to land on the counter. I sighed, just the sight of it reminded me of the terrible banging in my head. Hangovers were the worst. We sat side by side in the kitchen, disinterest, and distaste for one another high. I could bet if it was a smell, it'd be pungent."I feel the same way. " I replied monotonously taking a sip of the hot liquid, feeling it burn my throat. I glanced his way, staring at his brown hair ruffled, at his dark captivating green eyes. I placed a hand on my lips remembering the intense scene that occurred last night. I swallowed hard. How? I thought. How could I be interested?I was in love with his brother.
10
16 Chapters
How To Seduce The Alpha
How To Seduce The Alpha
The young and beautiful daughter of a hunter, Isabella Abegail Bannister was born with a silver spoon in her mouth and yet unlike other rich man's child, her life is more challenging than most. As the only descendant of her father, she has to become the head of their clan and that is to protect the human against wolves. The Northern region was at peace for a while ever since her family and the Alpha of the North signed an agreement of peace treaty. The wolves are not to enter the city, without permission from the head of the leader while the people in the City are forbidden to hunt the mountains that belong to the Vernice. The signed agreement was respected and maintained until the heirs took over. As Alpha Zero passes his leadership to his son Charles, Isabella becomes the head of the Bannister hunters. What would happen to peace and the promise of co-existence? When both of them have their grudge against each other. But faith will turn the tables around after Alpha Charles falls into the charm of a beautiful female hunter named Isabella. And Isabella needle his help in her fight against the other pack of wolves. That she wouldn't mind seducing him to get back at her enemies.
10
89 Chapters
How To Survive Werewolves
How To Survive Werewolves
Emily wakes up one morning, trapped inside a Wattpad book she had read the previous night. She receives a message from the author informing her that it is her curse to relive everything in the story as one of the side characters because she criticized the book. Emily has to survive the story and put up with all the nonsense of the main character. The original book is a typical blueprint Wattpad werewolf story. Emily is thrown into this world as the main character's best friend, Catherine/Kate. There are many challenges and new changes to the story that makes thing significantly more difficult for Kate. Discover this world alongside Kate and see things from a different perspective. TW: Mentions of Abuse If you are a big fan of the typical "the unassuming girl is the mate of the alpha and so everything in the book resolves around that" book, this book is not for you. This is more centered around the best friend who is forgotten during the book because the main character forgets about her best friend due to her infatuation with the alpha boy.
10
116 Chapters

Related Questions

What Inspired Ino Yamanaka'S Design In Naruto Franchise?

4 Answers2025-10-19 04:37:29
In 'Naruto', Ino Yamanaka stands out for her unique design and character traits, reflecting a blend of beauty and strength that resonates with fans. Her design is definitely inspired by the concept of a kunoichi, or female ninja, who embodies both femininity and combat prowess. The bright blonde hair paired with her blue eyes creates an eye-catching appearance that’s both vibrant and approachable, which is essential for her character as a member of Team 10. Furthermore, her clothing showcases a stylish yet practical outfit that consists of traditional shinobi gear with a fashionable twist. Ino’s propensity for flower motifs is not just for show; it symbolizes her nurturing side and connection to the natural world, enhancing her abilities in mind-based jutsu. The design elements reflect her personality—both tough and gentler, appealing to diverse fans. What really gets me excited is the level of depth in her character arc. As she matures throughout the series, her design subtly mirrors that growth, evolving from a brash teenager to a more self-assured young woman. The background story of her family, particularly her relationship with her mother, helps underscore her design choices; it adds meaning to how she sees herself in relation to her abilities and responsibilities as a Yamanaka. Overall, every element in Ino’s design tells a part of her story and reinforces her role in the 'Naruto' universe.

What Inspired The Character Design Of Tobi Akatsuki?

3 Answers2025-10-18 00:04:28
Tobi Akatsuki, oh boy, where do I even start? His design is a blend of something quite whimsical yet deeply enigmatic! When you take a closer look, it’s fascinating how he combines a kid-like charm with an undercurrent of menace. What really strikes me is that trademark mask; it’s not just a fashion statement! The mask starts as this fun, smiling face, but it quickly flips into something sinister, revealing the darker side of Tobi's personality and goals. This duality speaks volumes about the character itself—a seemingly innocent character hiding a much more complex and chaotic agenda. The color scheme is equally intriguing. The dark robes paired with that cheerful orange mask create an incredible contrast. It's almost like he’s wearing his own facade, maintaining that cheerful exterior while waging war behind the scenes. It gives off this vibe that he both blends in and stands out at the same time. I’ve often seen folks overlook how important the use of color is in character design. It’s more than aesthetic; it communicates personality, intentions, and even hints at motivations! When I think about other characters from 'Naruto,' the design choices often reflect their personal journeys or struggles. Tobi's evolution throughout the story, especially when you discover he’s Obito, layers the complexity of the design even further. It becomes a visual representation of conflict—between light-heartedness and hidden pain. In a way, his character design mirrors the struggles that many face in trying to balance their youthful dreams with the harsh realities of life. Pretty deep stuff, right?

What Are The Key Elements Of A Successful Comedy Thriller?

3 Answers2025-09-15 19:53:13
Crafting a comedy thriller is like juggling flaming swords; it demands a delicate balance between humor and suspense. One critical element is pacing. A brisk rhythm keeps the audience engaged while seamlessly shifting from laugh-out-loud moments to nail-biting tension. I adore how shows like 'Killing Eve' masterfully weave dark humor into tense scenarios, making every twist feel unexpected yet utterly delightful. The protagonist's quirks are also key—their relatability can create an intimate bond with viewers. When I watch a character stumbling through danger while cracking jokes, I find myself rooting for them, feeling their anxiety and excitement all at once. Another intersecting element is the absurdity of situations. The fun of comedy thrillers lies in elevating ordinary circumstances to ludicrous heights. For instance, the misunderstandings that spiral out of control, like in 'The Nice Guys,' are comedic gold that also nurture thrilling stakes. This absurdity keeps the audience on their toes, blurring the lines between the possible and the utterly ridiculous. Importantly, well-timed punchlines or absurd physical comedy can punctuate tense moments, offering brief respites before delivering the next shock. Lastly, a colorful ensemble cast adds depth and hilarity. A varied mix of characters with distinct personalities can enrich the narrative, leading to unique interactions that spark both laughter and suspense. In 'Hot Fuzz', the interactions between the straight-laced cop and the eccentric townspeople bring levity to the plot while keeping the tension high. The interplay between contrasting personalities amplifies the stakes and keeps the laughter flowing throughout the suspenseful chaos.

What Are The Unique Elements Of The Abc Murders Plot?

3 Answers2025-09-14 17:20:02
The plot of 'The ABC Murders' is a brilliant blend of mystery and psychological intrigue that really keeps you on your toes. From the start, the unique twist of the killer sending a series of taunting letters to Hercule Poirot sets the tone for this suspenseful story. Each location corresponds to a letter of the alphabet, and as Poirot races against time to decipher the clues, you can't help but feel the tension building. What makes this narrative so captivating is not just the clever murders, but the insight into Poirot's character—his sharp wit and relentless determination take center stage, making you root for him throughout each harrowing encounter. As the plot progresses, the depth of the victims adds an emotional layer that isn’t typically present in straightforward whodunits. For instance, rather than being mere plot devices, these characters come to life with backstories, creating a real sense of tragedy as they fall victim to the killer. You encounter the ever-looming question of why these particular individuals were chosen, which fuels the investigation while immersing you more into the psychological aspects of the murders. The relationship dynamics and social commentary subtly woven into the story add richness and provoke thought about justice and moral ambiguity in society. When you think the clues are leading you one way, Christie masterfully shifts your focus, leading to a shocking finale that leaves you pondering the intricacies of human psychology. It’s more than just solving a case; it’s an exploration of the minds involved, both of the detective and the killer. There's a satisfaction in piecing it all together, much like a jigsaw puzzle, and it reminds me of the thrill that mystery enthusiasts live for, making 'The ABC Murders' stand out in the genre.

How Does Patchouli'S Character Design Reflect Touhou Themes?

3 Answers2025-09-14 20:21:09
Patchouli Knowledge stands out as a vibrant character in the 'Touhou Project' universe, and her design intricately weaves together various themes central to the series. First off, the color palette is just striking—her lavender hair and robes give off this ethereal vibe, almost as if she's a walking embodiment of mysticism and magic. It ties beautifully with her role as a magician. You know, the colors also play into the idea of elemental magic, which is a recurring theme not just in her character but within 'Touhou' itself. The whole aesthetic really feels like it encapsulates the essence of the fantasy world ZUN crafted, where each character isn’t just there for show; they're like living symbols of complex ideas. Her design also incorporates the idea of a bookish scholar. You’ll notice she carries around a book, which is symbolic of her vast knowledge—a nod to the intellectual pursuit that the series often promotes. This detail roots her character deeply into the themes of knowledge and enlightenment. Alongside the flowing robes, it gives her this regal yet mysterious air, which makes you think twice before underestimating her. Really, her design resonates with that classic trope of the wise mentor in fantasy lore. Then, if you look at her overall demeanor, there’s this mix of aloofness and depth. It’s like she’s constantly wrapped up in thought or exploring new avenues in her magical research. This complexity makes her relatable and reflects the idea in 'Touhou' that everyone has their struggles—even powerful beings like Patchouli. Overall, she isn’t just a pretty face; she’s layered, and her design captures that essence perfectly.

How Does Susanoo Kakashi'S Design Differ From Others?

1 Answers2025-09-15 17:10:53
From the very beginning, I found Susanoo Kakashi's design to be refreshingly distinct compared to many characters in 'Naruto.' For one, while many shinobi suit their roles with traditional ninja attire—think of the Velcro-bound flak jackets and headbands—Kakashi dons an armored look that hints at his time spent on the battlefield. The armor doesn’t scream flashy but rather whispers of experience and hardship, a design choice that augments his character depth beautifully. His Susanoo form, unlike the vibrant hues of other users like Itachi or Sasuke, showcases a more muted blue that aligns perfectly with his laid-back personality. There’s an elegance in the simplicity of his design. It feels like a physical manifestation of Kakashi’s calm demeanor and immense power. Instead of overcomplicating things with layers upon layers of flashy designs, Kakashi pulls it off with a tasteful and appealing minimalism that sticks with you. Seeing this character evolve to such a unique Susanoo form also highlights the artistry in the show—each new transformation isn’t just about power, but storytelling through visual design. This gives a more personal touch to his character that resonates with me and, I believe, many fans out there. It’s also key to mention how his Sharingan eye makes its presence felt even more in that armor. While other Susanoo users show off their powers through vivid depictions, Kakashi’s formidable Sharingan gives a subtle nod to his Cartographer, which is undoubtedly a distinguishing trait. His designs remind me that character complexity often lies beyond extravagant visuals, merging functionality with intent and history.

How Did Amy Hennig Start Her Journey In Video Game Design?

3 Answers2025-09-17 15:40:17
Amy Hennig's entry into video game design is like a fascinating adventure story itself! She began her artistic journey studying film and video production, which laid the groundwork for her storytelling abilities. It’s intriguing how her passion for writing and narrative led her to the gaming world at a time when video games were still finding their way to the cutting edge of storytelling. Early in her career, Amy worked at various small studios, learning the ropes and sharpening her craft. You can almost picture her as a creative ninja, stealthily picking up all the secrets of character development and plot twists. Her big break came when she joined Naughty Dog, where she became the creative force behind the 'Uncharted' series! I mean, how epic is that? The way she crafted Nathan Drake's character and the thrilling adventures that unfolded felt almost cinematic, blending gameplay and storytelling in such a compelling way. It was refreshing to see a woman in a leading creative role during those years, breaking stereotypes and paving the way for future generations. You can feel her influence in gaming even now, and I love how she continues to advocate for narrative depth in interactive media. Truly inspiring! On a personal note, I’ve always been drawn to games that tell a story, so knowing there’s a brilliant mind like Amy’s behind some of my favorite titles just makes the experience that much richer. Her journey really shows how storytelling can transcend mediums and create unforgettable experiences for players.

How Does Pacific Rim Kaiju Design Influence Other Media?

1 Answers2025-09-18 20:12:19
It's incredible how the Kaiju from 'Pacific Rim' have left such a vibrant mark on not just the film industry but across various media! The sheer scale and imagination behind their designs is something that has captivated so many fans, myself included. Every Kaiju in the movie is unique, blending elements of various creatures while incorporating a kind of horror that makes you think, 'What kind of nightmare did this come from?' Most notably, the designs represented an evolution in how giant creatures were envisioned on screen, pushing the boundaries of what we expect when we see immense beings clash with towering robots. If you look closely at other franchises, you can see echoes of 'Pacific Rim's' aesthetic in multiple anime series and video games. For instance, titles like 'Attack on Titan' clearly draw from the sense of scale introduced by the Kaiju. The Titans feel both monstrous and oddly human at the same time, much like how some of the Kaiju exhibit an unsettling mix of familiar and alien traits. The design philosophy of making these creatures feel tangible yet otherworldly has definitely been influenced by the iconic designs in 'Pacific Rim'. It seems like every time there are massive beasts in a modern setting, there's a sprinkle of inspiration from this cinematic gem. Then there are games like 'Monster Hunter' and 'Shadow of the Colossus' that have ramped up their designs, too. In 'Monster Hunter', the various gigantic monsters possess such different artistical elements that probably took a page from the way that 'Pacific Rim' approached their Kaiju. The diversity is stunning, and each encounter feels like a predetermined dance of destruction! Meanwhile, in 'Shadow of the Colossus', the colossi aren't just imposing but also carry emotional gravity that I think resonates with how Kaiju are portrayed in 'Pacific Rim'. Each giant feels alive and integral to the environment, bridging the gap between nature and the supernatural. Not to mention, other movies have also started to embrace this trend. Think about the way modern reboots like 'Godzilla' and 'Kong: Skull Island' design their monsters. You can definitely feel the influence of 'Pacific Rim' when watching these films, with approaches to texture, movement, and even the minutiae of how they interact with their environments being elevated. These creatures are no longer just frightening; they’re layered and complex, bringing depth to their visual storytelling. It's genuinely fascinating how a film can revitalize an entire genre, inspiring not only filmmakers but also game designers and artists worldwide. The legacy of the Kaiju design in 'Pacific Rim' is not just in its immediate impact but how it has created a ripple effect throughout various creative spheres. It's always exciting to see how influences evolve and innovate in a space I care so much about!
Explore and read good novels for free
Free access to a vast number of good novels on GoodNovel app. Download the books you like and read anywhere & anytime.
Read books for free on the app
SCAN CODE TO READ ON APP
DMCA.com Protection Status