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google
guava
Java2015–2025
google / guava

guava

Google core libraries for Java

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37Distinct people
45Mentions
2Explicit recommenders
51.9KGitHub stars
REPOSITORY AT A GLANCE

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What it is

Google core libraries for Java

GitHub

Where it is used

No documented product use was verified in the last source check.

What people are saying

While you're not wrong RE: object references, Java does have the `final` keyword that you can apply to fields, local variables, method arguments, etc. This prevents the value…

OmarAssadi used a recommendation phrase. 2 indexed comments match. This is a phrase match, not a verdict.

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This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 1:49:46 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year45 dated mentions

Observed mentions: 2015-03-24 08:24:34 UTC to 2025-07-07 00:28:52 UTC.

024682015-01-01 00:00:00 UTC to 2016-01-01 00:00:00 UTC (exclusive): 3 mentions; 1 submissions, 2 comments20152016-01-01 00:00:00 UTC to 2017-01-01 00:00:00 UTC (exclusive): 8 mentions; 7 submissions, 1 comments2017-01-01 00:00:00 UTC to 2018-01-01 00:00:00 UTC (exclusive): 6 mentions; 1 submissions, 5 comments2018-01-01 00:00:00 UTC to 2019-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2019-01-01 00:00:00 UTC to 2020-01-01 00:00:00 UTC (exclusive): 7 mentions; 2 submissions, 5 comments2020-01-01 00:00:00 UTC to 2021-01-01 00:00:00 UTC (exclusive): 3 mentions; 1 submissions, 2 comments20202021-01-01 00:00:00 UTC to 2022-01-01 00:00:00 UTC (exclusive): 4 mentions; 1 submissions, 3 comments2022-01-01 00:00:00 UTC to 2023-01-01 00:00:00 UTC (exclusive): 6 mentions; 1 submissions, 5 comments2023-01-01 00:00:00 UTC to 2024-01-01 00:00:00 UTC (exclusive): 3 mentions; 1 submissions, 2 comments2024-01-01 00:00:00 UTC to 2025-01-01 00:00:00 UTC (exclusive): 1 mentions; 0 submissions, 1 comments2025-01-01 00:00:00 UTC to 2026-01-01 00:00:00 UTC (exclusive): 3 mentions; 1 submissions, 2 comments2025

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

View mention counts and date ranges
UTC ranges include their start and exclude their end. Select a period to filter the source evidence.
PeriodStart (UTC)End (exclusive, UTC)MentionsSubmissionsComments
20152015-01-01 00:00:00 UTC2016-01-01 00:00:00 UTC312
20162016-01-01 00:00:00 UTC2017-01-01 00:00:00 UTC871
20172017-01-01 00:00:00 UTC2018-01-01 00:00:00 UTC615
20182018-01-01 00:00:00 UTC2019-01-01 00:00:00 UTC101
20192019-01-01 00:00:00 UTC2020-01-01 00:00:00 UTC725
20202020-01-01 00:00:00 UTC2021-01-01 00:00:00 UTC312
20212021-01-01 00:00:00 UTC2022-01-01 00:00:00 UTC413
20222022-01-01 00:00:00 UTC2023-01-01 00:00:00 UTC615
20232023-01-01 00:00:00 UTC2024-01-01 00:00:00 UTC312
20242024-01-01 00:00:00 UTC2025-01-01 00:00:00 UTC101
20252025-01-01 00:00:00 UTC2026-01-01 00:00:00 UTC312

What Hacker News says

45 sources
charleslmunger·Jul 7, 2025
I've implemented multiple production versions of this problem (but not in JavaScript)[1], so maybe my view of this problem is miscalibrated... This feels both too easy and too hard for an interview? I would expect almost any new grad to be able to implement this in the language of their choice. Adding delays makes it less trivial, except that the answer is... Just use the function provided by the language. That's the right answer for real code, but what are you really assessing by asking it? [1] https://github.com/google/guava/blob/master/guava/src/com/go...
In Async Queue – One of my favorite programming interview questions
msteffen·May 26, 2025
Sorry for the slow reply here, but in Java, “final” variables can’t be updated to reference a different object, but the underlying object can be modified with method calls (e.g. you can append things to a “final” ArrayList, whereas in C++ you can’t append to a const vector. In C++, you mark methods const to indicate that they don’t mutate the underlying object, and only cost methods can be called on const variables). The Guava docs give an example of the defensive copying: https://github.com/google/guava/wiki/ImmutableCollectionsExp.... Any time an Immutable collection is created from another collection, the elements are deep-copied to avoid the possibility that they’re modified elsewhere, even if there’s no possibility of that happening. Even if you’re using e.g. an ImmutableList.Builder, the elements are copied when they’re Add()ed to t
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he Builder, so that they’re the same when you call build(). I’m not sure but I think even some mutable collections make defensive copies of their arguments. I believe that Josh Bloch (who was in charge of Java at Google when I joined) also advocates for this in his book. On writing this, it occurs to me that some kind of move constructor into these mutable collections might also do the job? Though you’d have to make sure there were no mutating references outside the mutable collection as well, which might require some kind of ownership model, so you might just wind up with Rust. Finally, this is dumb but it’s killing me: I meant to type 400qps to 1200qps/core.
In Too Much Go Misdirection
ryandv·Sep 5, 2024
It's worth noting that both languages cited (Python, C++) are multi-paradigm and therefore contain aspects of both OOP and FP; there are very few languages that are exclusively object-oriented or functional. The naming of the functools [0] stdlib package for Python's higher-order functions is illustrative in this respect, and there is an entire HOWTO for "implementing programs in a functional style" [1] in the Python docs. If you want to see object-orientation taken to the extreme, and how it makes writing programs in a functional style extremely unergonomic, you can read old-school Guava code from Java 6 and try to decipher all the line noise; there is even a caveat in its official documentation [2] that states, functional programming without Java 8+ requires awkward and verbose use of anonymous classes. Excessive use of Guava's
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functional programming idioms can lead to verbose, confusing, unreadable, and inefficient code. These are by far the most easily (and most commonly) abused parts of Guava, and when you go to preposterous lengths to make your code "a one-liner," the Guava team weeps. > It is a case of the paradigm not really meaning anything. It is an arbitrary bunching This is a case of throwing the baby out with the bathwater; just because we can't come up with a perfectly precise definition doesn't mean that we should dispense with rough heuristics and (perhaps crudely drawn) boundaries that serve as a useful clustering of related features. Try asking a machine learning or computer vision algorithm for the criteria it uses to categorize something as a "dog;" it's unlikely that you'll come up with something as precise as the definition of the Platonic ideal of a dog, but we can still use its model to recognize dogs with a reasonable degree of accuracy. [0] https://docs.python.org/3/library/functools.html [1] https://docs.python.org/3/howto/functional.html#small-functi... [2] https://github.com/google/guava/wiki/FunctionalExplained
In What's functional programming all about? (2017)
OmarAssadi·Feb 18, 2023Recommendation phrase
While you're not wrong RE: object references, Java does have the `final` keyword that you can apply to fields, local variables, method arguments, etc. This prevents the value from being re-assigned short of going out of your way to do reflection hacks and such. You can also apply it to classes themselves and prevent them from being inherited and modified that way. The only real 'gotcha' there is that, while it prevents whatever it is applied to from being reassigned, if the value is a mutable object of some sort (e.g., an array, mutable collection, etc), it, of course, does not prevent you from modifying the contents of the array, etc. However, Guava provides nice immutable collections to mitigate that issue [1]. It's been a while since I've written modern Java, but I want to say JDK 14? also brought records, which I believe are basically
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the equivalent of having `final` and `public` on everything as well as overriding the equality and hashcode functions on everything by default so that comparisons are done based on the contents of the object rather than the reference. And while I am sure many people are scared of the bytecode manipulation that it performs, Lombok [2] provides a lot of little utilities that make using immutable objects totally painless - e.g., applying `@Value` to the class generates all of the necessary boilerplate at compile time, or my favorite, `@With`, which generates methods for copying an immutable object with one of the fields changed (e.g., `val newUser = olduser.withName("Nayeon");`) Lombok also offers Kotlin-style extension methods [3] which can be nice too for this kind of thing. Though, in my experience, it is the only feature in it that has bitten me at times. [1]: <https://github.com/google/guava/wiki/ImmutableCollectionsExp...> [2]: <https://projectlombok.org> [3]: <https://projectlombok.org/features/experimental/ExtensionMet...>
In John Carmack on Functional Programming in C++ (2018)
the8472·Jul 22, 2022
Part of the problem is that handles on directories on which one can then use the the *at family of syscalls are not first-class citizens in many programming languages. Which in turn might be due to portability concerns with windows, e.g. Java's SecureDirectoryStream isn't available there[0]. Apparently windows does have an openat-like API[1], but it's low-level. Programmers aren't using them because the language standard libraries point them in the wrong direction. [0] https://github.com/google/guava/wiki/Release21#user-content-... [1] https://github.com/rust-lang/rust/blob/1c63ec48b8cbf553d291a...
In The trouble with symbolic links
throwaway2037·Feb 21, 2022
To compliment most other posters, they would use Maven Central: https://search.maven.org/ Here is an example library from Google called "Guava": https://search.maven.org/artifact/com.google.guava/guava/31.... You can find the source code on GitHub: https://github.com/google/guava On the right side of the page, you can find eleven (!) different wants to include this dependency (and) all of its transitive dependencies with just a few lines of configuration. Here is a list of the Top 10 downloads of open source Java libraries: https://mvnrepository.com/popular?p=1
In Why I Like Java (2014)
charleslmunger·Dec 26, 2021Recommendation phrase
Indeed. I recommend using tsan for java. https://wiki.openjdk.java.net/display/tsan/Main But the types of races I struggle with in java I suspect are similarly hard in Rust. Here's two pieces of concurrent code I struggled with: https://github.com/google/guava/blob/master/guava/src/com/go... https://github.com/google/guava/blob/master/guava/src/com/go... I'm not sure reasoning about the correctness of those would be easier in Rust, but if there are any rust experts reading this I'd love your perspective.
In State of Valhalla

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