diff --git a/crates/core/src/class.rs b/crates/core/src/class.rs
index 7f3a71a..accec4e 100644
--- a/crates/core/src/class.rs
+++ b/crates/core/src/class.rs
@@ -5,7 +5,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::{Error, Result};
 
-/// Data struct
+/// [`Class`] represents a source file. It is a handler.
 #[derive(Debug, Clone, Deserialize, Serialize, Hash, PartialEq, Eq, PartialOrd, Ord)]
 pub struct Class {
     /// Path relative to PACKAGE/java, without file extension.
@@ -14,6 +14,13 @@ pub struct Class {
 }
 
 impl Class {
+    /// Creates a new [`Class`].
+    ///
+    /// # Error
+    ///
+    /// * [`Error::MismatchedPackage`] if the provided `file_path` is absolute, and cannot be
+    /// subtracted to just its relative path within its parent package.
+    /// * [`Error::Io`] if the source file cannot be loaded and digested.
     pub fn new<P: AsRef<Path>>(package_src_root: P, file_path: P) -> Result<Self> {
         let mut file_path = file_path.as_ref().to_path_buf();
         if file_path.is_absolute() {
@@ -27,6 +34,17 @@ impl Class {
         })
     }
 
+    /// Returns a boolean representing if the class is up to date.
+    ///
+    /// # Criteria
+    ///
+    /// * The class path is local.
+    /// * The class has been compiled to `target/`
+    /// * The class' source file has not been updated.
+    ///
+    /// # Errors
+    ///
+    /// * [`Error::Io`]
     pub fn is_updated<P: AsRef<Path>>(&self, class_path: P) -> Result<bool> {
         // If the path is local and that file has not been updated.
         Ok(class_path
@@ -37,6 +55,13 @@ impl Class {
             && self.checksum == sha256::try_digest(self.path.clone())?)
     }
 
+    /// Updates the class' checksum.
+    ///
+    /// Only call this if you know that the class has been compiled successfully.
+    ///
+    /// # Errors
+    ///
+    /// * [`Error::Io`] if the source file cannot be loaded and digested.
     pub fn update<P: AsRef<Path>>(&mut self, package_src_root: P) -> Result<()> {
         self.checksum = sha256::try_digest(dbg!(
             package_src_root