Refactored verbose code constructs and QoL improvements

[Cespito]

Pull Request Etiquette

• [x] I have checked the PRs for upcoming features/bug fixes.
• [x] I have read the [contributing guidelines][contributing].

Changes

• [x] Internal code
• [ ] Library interface (affecting end-user code)
• [ ] Documentation
• [ ] Other: _____

Closes Issue: NaN

Description

This pull request makes the following improvements:

• Refactor verbose code constructs
• Fix raw use of parameterized class
• Delete unnecessary import

Details

• Added lambda expressions and utilized library methods to reduce code verbosity
• Removed unnecessary cast expressions
• Such raw use of generic types is valid in Java, but it defeats the purpose of type parameters and may mask bugs
• Replaced C like implementations in Java classes
• Removed unused imports
• Added log in exception catch on awaitReady() function
• Simplified this construct

if (currentIterator != null)
{
    if (!currentIterator.hasNext())
    {
        currentIterator.close();
        currentIterator = null;
    }
    else
    {
        if (findNext()) return true;
        currentIterator.close();
        currentIterator = null;
        }
    }

with

if (currentIterator != null)
{
    if (currentIterator.hasNext())
    {
        if (findNext()) return true;
    }
    currentIterator.close();
    currentIterator = null;
}

Benefits Improved code organization, maintainability, and readability. Reduced redundancy and enhanced robustness of the code.